If a CSP problem of $n$ variables can be decomposed into $m$ independent subproblems, where all subproblems have the same number of variables and all variables have the same domain of size $d.$ Then, the worst$-$case solution cost $($running time$)$ of the decomposed problem is

$($a$)\frac{n}{m}*d^m$

$($b$)m*d^{\frac{n}{m}}$

$($c$)m*d^m$

$($d$)n*d^{\frac{n}{n}}$

$($e$)$ None of the above