Cutting right back to the key point on the second question, and ignoring the side issue of stall definitions, the answer is C.
Cdi is proportional to Cl squared, but induced drag itself is a function of Cdi and V squared. In level flight -note the qualification - you can reach Cl max for your configuration at various speeds, depending on what Cl max your configuration gives you. As you fly slower V is coming down, and as lift is constant Cl required for level flight is going up proportional to the square of the speed reduction. Cdi is thus going up as Cl to the power 4. So with actual induced drag being Cdi times V squared, induced drag is going up as the square of the speed reduction. Got that?
This means that, however you adjust Cl with flap etc, you will still need a big Cl for slow flight, and this means a massively bigger Cdi and a bigger induced drag. This is a key practical point in handling rotate and lift-off. Do not rotate to extreme attitudes and do not lift off early or induced drag will bite you.
Dick W