Answer:
C. The objective teacher graded his students on their performance and not on their personality.
Step-by-step explanation:
In the original sentence, the word objective is used to mean without bias. Ranal does not use his emotions, or biases, when he makes decisions. In sentence C, the teacher is being describes as not using his emotions or biases to grade the students on their performance. In option A objective means real or observed. In option B and D objective means goal.