A. 7

B. 8

C. 9

D. 11

If two consecutive terms in the expansion of (x+a)^{n }are equal where n is a positive integer then (n+1)a/x+a is

If the sum of odd terms and the sum of even terms in the expansion of (x+a)^{n} are p and q respectively then p^{2}+q^{2}=

If the coefficients of (2r+1)^{th} term and (4r+5)^{th} term in the expansion of (1+x)^{10} are equal then r=

If the 3^{rd}, 4^{th} and 5^{th} terms of (x+a)^{n} are 720, 1080 and 810 respectively then (x,a,n)=

x^{n}-1 is divisible by x-k. Then the least +ve integral value of K is