I have . . . . . . . . for one month’s leave.

The correct answer is: B. requested

The other options are:

• A. demanded: This word means to ask for something in a very forceful or angry way. It is not the best word to use in this context because it suggests that the speaker is not being polite or respectful.
• C. wanted: This word means to have a strong desire for something. It is a less formal word than “requested” and it does not necessarily imply that the speaker has asked for permission or approval.
• D. asked: This word means to make a request for something. It is the most neutral word of the four options and it is the best word to use in this context.

The sentence “I have requested one month’s leave” means that the speaker has asked for permission to take one month off from work. It is a polite and respectful way of asking for something and it does not imply that the speaker is demanding or entitled.