I used to work on at one company, on one project, Project A. Now I work at another company on another project, Project B. None of my old coworkers are involved with Project B in any way.

I was asked a question in B that I was asked, and that I answered, in A. *Should I just forward the email answering the question in A to B?* 

I think I should because I'm lazy to rewrite it and, more importantly, the answer was accepted so that I can have a support from people from A to convince people from B that this answer is correct (which mean I have to forward the reply message too). 

I think I should not because it will show that I'm a lazy person.