Explanation:

The landlord is very ______ about cleanliness and finds fault with all his tenants.

To find the correct word for filling the blank we need to see the meaning of the given words.

1. fabulous - extraordinary, especially extraordinarily large.

2. pompous - affectedly grand, solemn, or self-important.

3. fastidious - very attentive to and concerned about accuracy and detail.

4. ominous - giving the worrying impression that something bad is going to happen; threateningly inauspicious.

So the correct answer for filling the blank is 'fastidious'. As this makes the sentence more meaningful , hence option 3 is the correct answer.