A pilot can respond with how many different codes on a Mode A/3 radar beacon transponder?

A Mode A/3 radar beacon transponder allows a pilot to respond with a total of 4096 different codes. This capability comes from the 12 bits of binary data that can be transmitted, where each combination of bits represents a unique code. Specifically, the transponder generates codes in the range from 0000 to 7777 in octal notation, or 0 to 4095 in decimal terms, thus allowing for 4096 unique responses.

This system is critical for air traffic control as it helps in identifying aircraft uniquely and maintaining safe separation in controlled airspace. Other options listed represent fewer unique codes and do not fully utilize the capability of the Mode A/3 transponder systems.