I was torn between A and E but didn't choose A because I don't know how long they have been a full-time employee. Maybe they were a part time employee before? LOL after seeing JY's explanation I was like Idk if that was too much of a stretch that led me to the right answer

Yes but I'm not so sure if its on the LSAT

But for example

There is a wallet that costs $40

Kaylen can afford the wallet with the money in her pocket

A necessary assumption would be that she has $40 dollars

A sufficient assumption would also be that she has $40 dollars

Hope this helps!