Step-by-step Solution:

To fill in the blank, we need a phrase or word that establishes a contrast between "he is well known" and "he is very honest." Let us analyze the options: (a) Despite the fact that - This phrase fits well as it introduces a contrasting idea. The complete sentence reads: Despite the fact that he is well known, he is very honest. This is a grammatically correct and meaningful sentence.\[\] (b) In spite of the fact that - This also fits correctly and conveys the same meaning as option (a). The complete sentence reads: In spite of the fact that he is well known, he is very honest.\[\] (c) Notwithstanding - While grammatically correct, it is less commonly used in this structure. It is more formal and might sound awkward in this context.\[\] (d) Even if - This does not fit the sentence properly because "even if" suggests a hypothetical condition, which is not implied here.\[\] Both (a) and (b) are correct, but (a) is more concise and preferred. \[\] Correct Answer: (a)