Which of these experiments sounds the most like it would be analyzed with an Independent-Samples t-test?

Group of answer choices

A study that looks at the attention span of a group of n=30 5-year-olds and then follows up with those same kids when they are 10-years-old

A study that compares tennis players vs. football players on their peak heart rate while playing their sports

A study that measures the knowledge of the transfer process for a group of Chaffey students, both before and after they attend an orientation

A study that gives patients a placebo on Monday and measures their pain, then has them back on Friday and gives them a real pain pill and measures their pain