"We're sorry for the delay in reply." or "[...] delay in replying."? [closed]

Solution 1:

You can start with the following forms:

1. We're sorry for the delay in sending our reply to you.
2. We're sorry for the delay in replying to you.

Form 1 uses reply as a noun. You can remove sending and to you as they are both implied in the communication, but reply still requires a determiner. This leaves We're sorry for the delay in our reply.

Form 2 uses replying as a verb. Removing the implied to you leaves your second choice.

Therefore between your two expressions, use the second (... delay in replying).

Solution 2:

"delay in reply" in not correct. You would say "Sorry for the delay in replying" or "Sorry for the delay in our reply". The first is more common.