The number of terms independent of $x$ in the binomial expansion of $\left(3x^2 + \dfrac{1}{x}\right)^{10}$ is
let m^{th} term is independent of x (here m is integer)
(3x^{2})^{m} x ($\frac{1}{x}$)^{10-m}
x^{2m-10}^{+m}
^{2m-10}^{+m=0}
m=10/3 not integer
Anser : A