Since the position of the Director and the Commander-in-chief are held by one person, Mr. Raichand, the article should be used only before one position which is placed first in the sentence. since it is already used before 'Director' no article should be used before 'Commander-in-chief'. Hence Option D is the correct answer. Using definite article 'the' before it would indicate that there are two different persons one director and one Commander-in-chief. Thus, Option C is incorrect. .Indefinite article 'a' or 'an' cannot be used before a particular position is being referred here. Therefore, Option A and B are also incorrect.