Final answer:
The most fitting answer for the sentence is 'complex' because it pertains to the intricacy and multifaceted nature of engineering math problems.
Step-by-step explanation:
The correct answer to fill in the blank in the sentence 'My father, an electrical engineer, is an expert at computing (______) math problems' is b) Complex. This option is the most appropriate because electrical engineering typically involves solving complex mathematical problems that require a deep understanding of various mathematical concepts and principles. These problems can be challenging, complicated, and difficult, but the term 'complex' specifically refers to the intricacy and multifaceted nature of the mathematical problems often encountered in the field of engineering.