The correct experiment set-up for separating a substance by sublimation is:
(A)

(B)

(C)

(D)

Hint :In the given options, C is the correct option.
 So in order to separate a mixture from non-volatile compound to volatile one, sublimation process is used.
The mixture is first heated with the help of a burner. The solid compound sublimes after heating and turns into a gaseous state. Then the gas passes out from the cotton plug.

Complete Step By Step Answer:
In the given options, C is the correct option.

In this setup there is a base in which their burner is placed and a sheet is present at the base of the china dish, the solid is placed inside the funnel and the cotton plug is placed at the top of it.
Here, sublimation is generally a process in which the solid state phase is changed into gaseous state without converting it into a liquid form.
The mixture is first heated with the help of a burner. The solid compound sublimes after heating and turns into a gaseous state. Then the gas passes out from the cotton plug.

Note :
Sublimation is a process in which matter undergoes direct phase transition from a solid state to gas. This won’t involve the liquid transition state. For example we know that ammonium chloride is the perfect example of changing a solid to directly in tis gaseous form on constant heating. So in order to separate a mixture from non-volatile compound to volatile one, sublimation process is used.