Final answer:
The type of contract formed in this scenario is an Express Contract, where the terms of the agreement are explicitly stated in writing or verbally.
Step-by-step explanation:
The type of contract formed when Jose agrees in writing to sell Cindy 100 lobsters for $15 each, payable by credit card, in exactly 30 days is Express Contract.
An express contract is one in which the terms of the agreement are explicitly stated, either verbally or in writing. In this case, both Jose and Cindy have agreed to a specific set of terms regarding the sale of lobsters.
This contract also involves consideration (the exchange of something of value) from both parties, as Cindy has agreed to pay $15 for each lobster and Jose has agreed to deliver 100 lobsters.