Thanks for your reply, hvianna.
Referring to the code for the first attempt which was the closest I got:
<a class="small round button formsubmit" href="contact-us?subject='Brochure Request'">Request</a>
the subject is defined as: Brochure Request which is the dropdown menu entry I’m trying to target.
The thing is I don’t want to make that dropdown menu entry the default option as there will be other instances where I want to target a different menu option.
Any other thoughts?