Answer
$35\frac{1}{b^8}c^3$
Work Step by Step
The $r+1$ th term in the binomial expansion of $(x+y)^n$ is:
$\binom{n}{r}x^{n-r}y^r$
Here $x=\frac{1}{b^2}$, $y=c$, $n=7$:
$r+1=4$
$r=3$
The indicated term is:
$\binom{7}{3}(\frac{1}{b^2})^{7-3}(c)^3=35\frac{1}{b^8}c^3$
