Why the other options are wrong:

• new gym membership plans.: The report suggests devices and equipment, not new gym membership plans.
• new research in sports.: The source recommends consumer fitness gadgets rather than describing a sports research study.
• new technology in space travel.: Space travel is not discussed.

Correct Answer: socially acceptable.

Why this is correct: The report explicitly says wearing a smartwatch at the gym or elsewhere is now socially acceptable. This is the change in public acceptance that the question asks about.

Why the other options are wrong:

• important for sports.: The passage does not say a smartwatch is necessary or important for participating in sports. It says wearing one is socially acceptable.
• part of everyday life.: Part of everyday life is a broader claim than the stated acceptance of wearing a smartwatch.
• a status symbol.: The report does not describe the watch as a status symbol. The stated change is social acceptance.

Correct Answer: a personalized fitness coach.

Why this is correct: The report says a smartwatch acts as a personalized fitness coach by providing health metrics, advice and feedback. Personalized fitness coach is the comparison it uses.

Why the other options are wrong:

• a replacement for every smartphone.: The watch provides fitness information and guidance; the report does not say it replaces every smartphone.
• a personal doctor.: Medical care or diagnosis is not claimed for the watch, so it is not described as a personal doctor.
• an emergency call service.: Emergency calling is not the watch's role described in this report.

Correct Answer: hydration.

Why this is correct: The report identifies hydration as one of the most overlooked keys to health and fitness. It makes this point while describing smart water bottles and water intake.

Why the other options are wrong:

• rest.: Rest is not the overlooked factor identified in the discussion of water intake. The report names hydration.
• sleep.: Sleep is mentioned among smartwatch measurements, but it is not named as the overlooked key in this part of the report.
• workout.: Exercise is a goal of the fitness advice, but the overlooked factor specifically named is hydration.

Correct Answer: invest in quality running shoes with built-in sensors.

Why this is correct: The report recommends quality running shoes to pursue a personal best or meet the running challenge, then describes built-in sensors that record running data.

Why the other options are wrong:

• replace all running with gym classes.: The recommendation prepares people for running rather than replacing it with gym classes.
• plan to rest instead of running.: The report encourages hitting the trail; it does not recommend resting instead of running.
• avoid technology in running equipment.: Recommending sensor-equipped shoes contradicts avoiding technology in running equipment.