Which of the following are the central-bank functions performed by the Hong Kong Monetary Authority?
(1) supervision of banking activities
(2) financing the budget deficit
(3) maintaining the stability of the exchange rate of the Hong Kong dollar
(4) cheque clearing
A. (1) and (3) only
B. (1) and (4) only
C. (2) and (3) only
D. (2) and (4) only