It is given, Sn=2n2+n Sn−1=2(n−1)2+(n−1) Sn−1=2n2−3n+1 Tn=Sn−Sn−1=2n2+n−2n2+3n−1=4n−1 Tn=4n−1 The terms are 3,7,11,15,19,23,27,....... 27 is the first term in the series divisible by 9 . 27 is the 7 th term. Therefore, the least possible value of n is 7 . The answer is option C.