Since substituting $x=1$ we get $\frac{0}{0}$ which is indeterminate.
After applying L'Hospital rule, we get $\dfrac{(7x^{6} -10x{^4})}{(3x^{2} - 6x)}$
Now substituting $x=1$ we get $\left(\frac{-3}{-3}\right) =1.$
Hence, answer is $1$.
Correct Answer: $C$