Week 1 : 1 customer tells 3 friends
Week 2: 3 new customers tell 9 friends
Week 3: 9 new customers tell 27 friends
If w represents number of weeks, then (C) represents the model appropriately. Let's see how:
Putting w = 1 , 2 and 3 in each of the options
(A) 3w: 3 for week 1, 6 for week 2, 9 for week 3 ⇒ INCORRECT
(B) w^3: 1 for week 1, 8 for week 2, 27 for week 3 ⇒ INCORRECT
(C) 3^w: 3 for week 1, 9 for week 2, 27 for week 3 ⇒ CORRECT
(D) 3w^3: 3 for week 1, 24 for week 2, 81 for week 3 ⇒ INCORRECT
Hence, the answer is (C)
