Which question is a statistics question that anticipates variability?

a) how do i rate the taste of ice-cream on a scale of 1 - 10?

b) how does my brother rate the taste of ice-cream on a scale of 1 - 10?

c) does my father or my mother like the ice-cream from the grocery store better?

d) which brand of ice cream is preferred by the people shopping at a grocery store?