Consider the following.
Assertion (A): Alum is applied to stop bleeding from cuts.
Reason (R): Blood is a colloidal system containing colloidal particles. The aluminium ions of alum have high coagulating power so the blood gets coagulated.
Select the correct answer:

A. Both (A) and (R) are true and (R) is the correct explanation of (A)

B. Both (A) and (R) are true, but (R) is not the correct explanation of (A)

C. (A) is true, but (R) is false

D. (A) is false, but (R) is true

Answer: Option A