Question

where is the bold thamo being used in the sentence?
timon enjoys scuba diving; as a matter of fact, he
is a licensed instructor.
between two complete thoughts
interrupting one complete thought

Explanation:

First, identify the complete thoughts. "Timon enjoys scuba diving" is one complete thought, and "he is a licensed instructor" is another. The bold THAMO "as a matter of fact" is placed between these two complete thoughts (separated by a semicolon), connecting them. It is not interrupting a single complete thought.

Answer:

A. Between Two Complete Thoughts