Answer
(c) $\lambda_{A}\gt\lambda_{B}$
Work Step by Step
$\lambda_{A}=\frac{0.693}{t_{1/2}\,of\,A}=\frac{0.693}{3.5\,days}=0.198/day$
$\lambda_{B}=\frac{0.693}{t_{1/2}\,of\,B}=\frac{0.693}{7.0\,days}=0.099/day$
Clearly, $\lambda_{A}\gt\lambda_{B}$.
Therefore, option (c) is the correct one.