To find the expected semester exam score for a student who did not attend the course, we can substitute \( x = 0 \) into the equation of the line of best fit, which is given by:
\[ y = 0.7x + 37 \]
Substituting \( x = 0 \):
\[ y = 0.7(0) + 37 \] \[ y = 0 + 37 \] \[ y = 37 \]
Therefore, the teacher should expect a test score of 37 for a student who did not attend the course.
The correct answer is C. 37.