The correct answer is: B. The employer told the workman that he could not pay him higher wages.
The employer is the one who is paying the workman, so it makes sense that he would be the one to tell the workman whether or not he can be paid higher wages. The employer is also the one who has the authority to make this decision, so his word is final.
The other options are incorrect because they do not accurately reflect the relationship between the employer and the workman. Option A is incorrect because it implies that the workman is the one who is deciding whether or not he can be paid higher wages. Option C is incorrect because it implies that the employer is forbidding the workman from paying higher wages. Option D is incorrect because it implies that the employer is warning the workman that he cannot pay him higher wages.
In conclusion, the correct answer is: B. The employer told the workman that he could not pay him higher wages.