Answer
(a) $I_L = 1.0~A$
(b) $I_L = 4.0~A$
(c) $I_L = 1.0~A$
Work Step by Step
We can write an expression for the peak current:
$I_L = \frac{\epsilon_0}{L~\omega}$
(a) If the inductance is doubled then the peak current is decreased by a factor of $\frac{1}{2}$
$I_L = 1.0~A$
(b) If the peak emf $\epsilon_0$ is doubled then the peak current is increased by a factor of $2$
$I_L = 4.0~A$
(c) If the frequency $\omega$ is doubled then the peak current is decreased by a factor of $\frac{1}{2}$
$I_L = 1.0~A$