Plants are always herbs in which of the following families?

Persistent calyx is a characteristic of

Which of the following characters are related to the family $Malvaceae$?
$(a)$ Five stamens
$(b)$ Marginal placentation
$(c)$ Infinite stamens
$(d)$ Twisted aestivation

Cinchona belongs to the family .....

Coffee and quinine are obtained from plants of the family ..........

What is true for the plant shown in the given figure?