Thomas contacted Welsh, a realtor, and asked him to be looking for property that is at least $20$ acres, zoned commercial, within the city limits$.$ Welsh responded that he would look for such a property and reminded Thomas that the typical finders fee in such a situation is $10\%$ of the property asking price. If Thomas responds with "I know," the parties have formed an express contract by mutually manifesting assent to the essential terms.

a$.$ True

b$.$ False