Explanation

(c) Here resistances 4$\ \Omega,\ 6\Omega,\ 12\Omega$ and 24$\ \Omega$ are in parallel. Their effective resistances, $R_{P}$ will be
$\frac{1}{R_{P}} = \frac{1}{4} + \frac{1}{6} + \frac{1}{12} + \frac{1}{24}$
$= \frac{6 + 4 + 2 + 1}{24} = \frac{13}{24}\ or\ R_{P} = \frac{24}{13}$
Total resistance between $A$ and $B$
$= 3 + \frac{24}{13} + 5 = \frac{128}{13} = 9.85\ \Omega$