Which type of contraction requires the muscles to "activate" but have no movement or change in muscle length?

Ithink it's d or it can be itger

Thats a weird question but ill answer it i think 5.

Is this used on a test? ?

(a) is not correct because one does not get increased cholesterol  from lifting weights.(b) is not correct because lifting weights cannot reduce the risk of a hereditary disease.(c) is not correct because back pain isn't a benefit! and plus, if he lifts weights properly, he should not have back pain.(d) is the correct answer because his ligaments will gain mass, making it easier for him to carry heavier weights and he will also be stronger!