Answer:
The correct answer is : C. Neither breached the contract because there is no contract until Friday.
Explanation:
As the contract will only become valid when both the parties Mohan and ACME sign up and this will only happen on Friday. But as Mohan is informed by the Acme on Tuesday that they can not hire him before signing up the contract that is scheduled on Friday. Since there is no valid agreement between parties, no breach of contract occurred.
Thus, the correct answer is option C. Neither breached the contract because there is no contract until Friday.