which of the following is most likely the next step in the series?

which of the following is most likely the next step in the series?
Answer
Explanation:
Step1: Analyze the pattern
The first figure has 2 dots in a 1 - row by 2 - column arrangement. The second figure has 6 dots in a 2 - row by 3 - column arrangement. The third figure has 12 dots in a 3 - row by 4 - column arrangement.
Step2: Determine the next step
The number of rows and columns in each figure is increasing by 1 each time. So the next figure should have 4 rows and 5 columns. The number of dots in a 4 - row by 5 - column arrangement is $4\times5 = 20$.
Answer:
C.