Correct Answer - Option 2 : G.P.
Given :
a, b & c are in A.P
Concept used :
If the difference between the number of a group is the same then they are in A.P.
If the sequence of numbers in which the ratio between consecutive terms is constant then they are in G.P.
Calculations :
a, b & c are in A.P
Let a, b, c be 1, 2 & 3
So,
⇒ 3a = 3 , 3b = 3² = 9, 3c = 3³ = 27
3c/3b = 3, 3b/3a = 3
So this is a G.P as ratio is constant.
∴ The correct choice is option 2.