After observing this pattern, amira made a conjecture for the next number in the pattern. 4, 12, 36, 108, 324, … a.332 b.432 c.972 d.1296

First, lets observe this pattern.
We can notice that each number when multiplied by 3 gives the following number as:
4 x 3 = 12
12 x 3 = 36
36 x 3 = 108
108 x 3 = 324

Based on this, the next number in the pattern will be: 
324 x 3 = 972

The right choice is:
c. 972