Read each sentence to find out whether there is any grammatical error in it. The error, if any will be in one part of the sentence. The letter of that part is the answer. If there is no error, the answer is 'D'. (Ignore the errors of punctuation, if any). (solve as per the direction given)

The sentence reads: "Having received your letter this morning, we are writing to thank you for the same." Let's break it down to identify any grammatical error:

1. Option A - Having received your letter:
   • The phrase "Having received your letter" is a correct participial phrase. It indicates that the action of receiving the letter happened before the action of writing. This part is grammatically correct.
2. Option B - this morning, we are writing:
   • The phrase "we are writing" is in the present continuous tense. However, it does not fit well with the participial phrase "Having received your letter" (which is in the past tense). The sentence would be grammatically correct if it used the simple past tense, such as "we wrote" instead of "we are writing."
   • This is the part with the grammatical error.
3. Option C - to thank you for the same:
   • The phrase "to thank you for the same" is correct and appropriately follows the main action of writing. There is no error here.
4. Option D - No error:
   • The error is found in Option B, where the tense usage does not match the intended meaning. So, this option is not correct.
5. Final Answer:
   • The error is in Option B. The correct answer is B.