Option B - Limited Trade

Trade begins under strict rules.

The visitors can buy and sell goods, but they cannot travel freely through your kingdom.

Then something concerning happens.

They approach you with an offer.

A neighboring kingdom is your longtime rival.

The visitors offer weapons and military assistance if you give them special trading privileges.

What do you do?

B1. Accept. Defeating your rival is worth it.

B2. Refuse. You don't want foreigners involved in local politics.

B3. Buy their weapons but refuse to give them special privileges.