Assertion (A) : A fair coin is tossed n times. If the probablities of getting 4,5 and 6 heads be in A.P then n is equal to 7,14
Reason (R ) : If `.^(n)C_(r+1)`, `.^(n)C_(r )`, `.^(n)C_(r+1)` are in A.P then `(n-2r)^(2)=n+2`
The correct answer is

Options

A. Both A and R are true, R is the correct explanation of A
B. Both A and R are true, R is not the correct explanation of A
C. A is true but R is false
D. A is false R is true

Answer

A