Question

as the soviet union began to fall, she bounced from an economics department — her thesis was on regulated costs in machine - tool building enterprises — to english instruction to the wobbly business world of the 1990s.
source: new york times
in this sentence, thesis means:
the calendar of a court
address to an absent or imaginary person
a treatise advancing a point of view resulting from research
a statement that cleverly avoids an unpleasant truth

Explanation:

In an academic context, a thesis is a written work presenting research - based arguments. Here, the person's thesis was on regulated costs in machine - tool building enterprises, which implies it's a research - based treatise.

Answer:

C. a treatise advancing a point of view resulting from research