Why haven't we seen dramatic inflation over the past twenty years given that the monetary base has increased by trillions of dollars?

a.Much of the increase in the monetary base has ended up as bank excess reserves.

b.The increase in the monetary base hasn't translated in dramatic increases in the money supply.

c.Increases in the money supply have been largely offset by declines in velocity.

d.All of the above.

e.None of the above.

Ty-ped and correct answer please. I will rate accordingly.