Final answer:
The correct answer is c) Are pleased, as 'one of the workers' suggests a singular subject from a plural group and calls for a plural verb.
Step-by-step explanation:
The correct answer to the question "Every one of the workers with the new agreement" is c) Are pleased. This is because when we refer to everyone or similar indefinite pronouns such as everybody, anyone, somebody, etc., they are considered singular and therefore, the verb should also be singular. However, in this specific example, the subject "one of the workers" implies a singular subject out of a plural group (the workers), thus it is more appropriate to use a plural verb when speaking about more than one person, which is the collective workers in this context. Therefore, 'are' is the correct form to use.