I think that correct answer is b. I am not sure if there is more than one correct answer. Which of the following Fed actions will increase bank...

I think that correct answer is b... I am not sure if there is more than one correct answer.

Please help to understand!

Which of the following Fed actions will increase bank lending:-

 a)The Fed raises the reserve ratio from 10 percent to 11 percent. 

b)The Fed lowers the discount rate from 4 percent to 2 percent

c)The Fed reverse repos $10 billion worth of Treasury bonds to non-bank financial firms.

d)The Fed raises the discount rate from 5 percent to 6 percent.