Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

An increase in the time between when an order to trade a security is placed and when the order is executed most likely indicates that market efficiency has:
Option A:decreased.
Option B:remained the same.
Option C:increased.

Answer: A