Answer:
a defensive open market sale
Explanation:
The Trading Desk at the Federal Reserve Bank of New York is in charge of carrying on the short term objectives specified by the Federal Open Market Committee (FOMC). The Trading Desk engages in open market operations (OMO), which are the purchase and sale of Fed's securities.
In this case, in order to lower the float, the Trading Desk should carry on a defensive open market sale which should temporarily lower the interest rate. Defense open market operations are designed to offset temporary fluctuations, they shouldn't affect overall monetary policy.