Please help me with the right option

Ahmed is considering his plans for the coming weekend. He is currently working as a marketing specialist in a big advertising company. He normally spends the weekend with family but this weekend he is thinking of going on a camping trip that would cost him about $1,900. At the same time, his manager asked him whether he can help during the weekend and the company will be willing to pay him an overtime bonus of $1,000. If Ahmed goes on the camping trip, he can manage to provide a number of quick consultancy services that would earn him around $2,500. If Ahmed decided to go on the camping trip what would be the opportunity cost of that decision ($)? O a. 600 O b. 1,000 O c. 2,500 O d. 1,900 O e. None of the given answers