Correct Answer: D
Explanation:
The second half of the sentence confirms that the teacher�s approach to grading is unpredictable. Hence, �whimsical� fits the sentence as it describes something fickle or changeable and rather random. �Ambivalent� with its suggestion of something wavering and uncertain is the second correct answer. �Authoritarian� and �strict� are synonyms but do not fit the meaning of the sentence. [hidebound = fixed and rigid; tardy = slow]