c
(c)Lowest resistance will be in the case when all the resistors are connected in parallel.
$\frac{1}{R} = \frac{1}{{0.1}} + \frac{1}{{0.1}}$ ....... $10$ times
$\frac{1}{R} = 10 + 10$ ....... $10$ times
$\frac{1}{R} = 100$ i.e. $R = \frac{1}{{100}}\,\Omega $