为什么不选C?

问题如下：

An analyst gathers the exchange rates from Dealer A in Exhibit 1.

The analyst calls Dealer A with specific details of the transaction and asks to verify the USD/GBP quote. Dealer A calls her back later with a revised USD/GBP bid/offer quote of 1.5760/1.5768.Using Exhibit 1, which of the following would be the best reason for the revised USD/GBP dealer quote of 1.5760/1.5768?

选项：

A.A request for a much larger transaction

B.A drop in volatility in the USD/GBP market

C.A request to trade when both New York and London trading centers are opened

解释：

Larger transactions may be harder for the dealer to sell in the interbank market and would likely require the dealer to quote a wider spread (lower bid price and higher offer price).