The wettability of a surface by a liquid depends primarily on

The angle of contact is $120^{\circ}$ when a cylindrical rod is vertically placed in a liquid. If the same rod is placed horizontally in the liquid, then the angle of contact is (in $^{\circ}$)

By adding soluble impurity in a liquid,the angle of contact

Due to capillary action,a liquid will rise in a tube,if the angle of contact is

Given below are two statements: One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Clothes containing oil or grease stains cannot be cleaned by water wash.
Reason $(R)$: Because the angle of contact between the oil/grease and water is obtuse.
In the light of the above statements,choose the correct answer from the options given below.

The liquid (mercury) meniscus in a capillary tube will be convex if the angle of contact is