Answer: Melissa, a proven salesperson from a competing firm
Step-by-step explanation:
The best candidate for the role of a sales person is Melisa who is a salesperson from a competing firm. Since the objective of Eric Brown who is the human resource manager is to minimize training costs post recruitment, Melisa is the right candidate.
Melisa already has lots of experience as a salesperson in a previous company so,she is experienced and hence won't need to undergo any training unlike a product developer or engineer who need to undergo some trainings.