Meaning: 'Make' in this context means to earn or generate money from a product or service.

Wrong options:

• ensure: 'Ensure' means to guarantee or make certain, which does not fit the context of generating money directly.
• offer: 'Offer' implies providing something to someone, but it does not convey the action of earning money from the app.
• pull: 'Pull' typically means to draw or attract, which is not relevant to the context of generating income.

Correct answer: willing

Explanation: The adjective 'willing' correctly describes the users' readiness to pay, fitting grammatically as it follows the verb 'are' in the present continuous tense. It aligns with the context of discussing user willingness to spend money.

Meaning: 'Willing' means being ready or prepared to do something, in this case, to pay for features of the app.

Wrong options:

• willingly: 'Willingly' is an adverb and does not fit the grammatical structure needed here, which requires an adjective to describe users.
• are willing: This phrase is grammatically correct but unnecessarily verbose; the simpler form 'willing' suffices in this context.
• that willingness: This phrase is a noun form and does not fit the sentence structure that requires an adjective.

Correct answer: charge

Explanation: The verb 'charge' fits grammatically as it indicates the action of setting a price for subscriptions, aligning perfectly with the context of pricing strategies. It is in the base form, suitable for the infinitive structure following 'to'.

Meaning: 'Charge' means to ask for a specific amount of money in exchange for a service or product.

Wrong options:

• prepare: 'Prepare' means to make something ready, which does not relate to setting a price for subscriptions.
• illuminate: 'Illuminate' means to light up or clarify, which is unrelated to the context of pricing.
• evaluate: 'Evaluate' means to assess or appraise, which does not convey the action of setting a price.

Correct answer: keep

Explanation: The verb 'keep' fits grammatically as it indicates the ongoing action of maintaining or continuing to adjust the pricing plan, aligning with the context of managing a pricing strategy. It is in the base form, suitable for the infinitive structure following 'to'.

Meaning: 'Keep' means to continue doing something or maintain a certain state, in this case, adjusting the pricing plan.

Wrong options:

• turn: 'Turn' implies changing direction or position, which does not fit the context of maintaining a pricing strategy.
• provide: 'Provide' means to supply or make available, which does not convey the action of maintaining adjustments.
• expose: 'Expose' means to reveal or uncover, which is not relevant to the context of adjusting pricing.

Correct answer: affordability

Explanation: The noun 'affordability' fits grammatically as it refers to the quality of being affordable, which is relevant in the context of balancing price and profit margins. It serves as a noun complement to 'balance'.

Meaning: 'Affordability' refers to the state of being affordable or reasonably priced, especially in relation to what customers can pay.

Wrong options:

• assignments: 'Assignments' refers to tasks or duties, which does not relate to the context of pricing and profit margins.
• borders: 'Borders' refers to boundaries or edges, which is unrelated to the financial context of the sentence.
• participants: 'Participants' refers to individuals taking part in something, which does not fit the context of pricing strategies.