Answer:
c. Someone who is strict.
Step-by-step explanation:
A taskmaster is someone who takes great care in his work and also makes others work very hard without any chance of lagging. He/ she makes sure that things are done and the work is going well, staying on track.
In the given sentence, when Mr. Ludwig is described as a taskmaster, the speaker simply means that he is a strict person who makes sure that everyone works hard and gets the work done without any delay. Such type of person is similar to a bossy manager or superior, who makes the employees work hard and not lag in their productivity.
Thus, the correct answer is option c.