[Grammar] Present perfect tense or Present tense of Past tense

[Shin0131]

I am writing a very formal letter to my customer and wondering whether the tense should be past, present or present perfect tense. Here are the sentenses;

A. It is a great pleasure to be given the opportunity of informing you that with the effective date of July 1, 2014, I have assumed my duties as the Chairman of company A. (Present Perfect)

B. It is a great pleasure to be given the opportunity of informing you that with the effective date of July 1, 2014, I assumed my duties as the Chairman of company A. (Past tense)

C.It is a great pleasure to be given the opportunity of informing you that with the effective date of July 1, 2014, I assume my duties as the Chairman of company A. (Present tense)

Because I specify the date (past) , will it have to be a past tense? Or because it is since the date, will present perfect be suitable?

Please let me know. Thank you in advance.

 

[Tarheel]

How about:

Effective July 1, 2014, I assumed the duties of Chairman of Company A.

(You may, of course, add anything to that that you want to.)

 

[Shin0131]

Thank you very much for the information.

 

[Rover_KE]

Shin, there is no need to write a new post to say Thank you. Simply click the Thank button on any posts you find helpful. It means that we don't have to open the thread again to read your new post and then find that it doesn't include any new information or an additional question. It saves everybody's time.