Which of the following option mentions an appropriate concluding sent…

The correct answer is Option (1) → I hope to hear from you soon

While all the options could be used in certain contexts, the most appropriate concluding sentence for a Letter of Enquiry should be polite, professional, and express your anticipation for a response. Here's a breakdown of the options:

☀ I hope to hear from you soon: This is a standard and well-regarded closing sentence for a Letter of Enquiry. It expresses your interest in receiving a response without being demanding.

☀ Please write a reply as soon as possible: This might be perceived as slightly pushy, especially if the timeframe for a reply wasn't previously mentioned. It's best to avoid sounding demanding.

☀ Call the concerned authority if you have any doubt: This shifts the responsibility to the recipient and isn't ideal for a closing sentence. You've already communicated your enquiry, so calling shouldn't be the first option presented.

☀ Call the undersigned: This is too informal and doesn't provide contact information. It's best to stick to traditional closing phrases and include your contact details separately.

Therefore, the most appropriate concluding sentence for a Letter of Enquiry is:

I hope to hear from you soon.

This is professional, polite, and expresses your anticipation for a response without being demanding.