The word "it" in the saying "use it or lose it" (Paragraph 1) refers to ______.

A．The population of elderly people.
B．Nuclear weapon.
C．Standard of living.
D．Violence in crime.

A．All the students would like a formal ball.
B．Raising money will be hard.
C．The festival will begin the year nicely.
D．The club needs some sports as well.