I would say the answer to this question is none of the above.

The condition in the question stem can be demonstrated as follows:

LDM --> T

Therefore, we flip and negate to get the correct assumption.

T ---> LDM

In other words, if there is no traffic --> Larry did not drive in the morning. Keep in mind its not just that it is not morning, it is that larry did not drive in the morning). I feel like with the LSAT this is a pretty key point that they won't miss in the correct answer choice.

I would review the lesson on sufficient and necessary assumptions.