Give reason: The wing of a duck does not get wet in water.

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.

When the temperature is increased,the angle of contact of a liquid:

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

How does the angle of contact depend on temperature?

$A$ liquid does not wet the solid surface if the angle of contact is