solve??????

ⁿ⁺¹c_r and ⁿc_r+1 both are positive so (k²-3) 0 i.e. | k | 3

and also n+1r and nr+1  ==>  nr+1   and r0

(k²-3) = ⁿ⁺¹c_{r /}  ⁿc_r+1 = (n+1) (r+1) / (n+1-r) (n-r)

(n+1)  / (n+1-r) 1 and (r+1) / (n-r)  (r+1)  1

(k²-3) can be greater then 1 or less then 1 depending on the values of n and r

so option c is incorrect. and a,b,d are right answers.