$(10$ pts$)$ Calculate values for $H_{},B_{},$ and $M_{}$ at $=c$ for a coaxial cable with $a=2\mathrm{.}5mm$ and $b=6$ mm if it carries a current $I=12A$ in the center conductor, and $=3\frac{H}{m}$ for for and $=10\frac{H}{m}$ for Use $c=$: $($a$)3$ mm ; $($b$)4$ mm ; $($c$)5$ mm $.$