Other Things Constant, Which of the Following Would Cause the M1

Other things constant, which of the following would cause the M1 money supply to decline?

A) an increase in the quantity of U.S.currency held overseas
B) a shift of funds from interest-earning checking deposits to money market mutual funds
C) a reduction in the general public's holdings of currency outside of banks because debit cards have become more popular and widely accepted
D) a shift of funds from money market mutual funds into stock and bond mutual funds because the fees to invest in the latter have declined