Correct Answer - Option 2 : 2
The age of the youngest person = 17 years
The age of the oldest person = 22 years
Also, as there are six cousins, implies, their ages are 17, 18, 19, 20, 21 and 22 years.
The age of E = 22 years (the oldest person)
A is older than B. A is one year older than C.
⇒ E > A > C > B
C is older than D.
⇒ E > A > C > B; C > D
F is somewhere between B and D in age.
⇒ E > A > C > B/D > F > B/D
Possibilities: E > A > C > B > F > D and E > A > C > D > F > B
Hence, there are two possibilities.