Fill in the blanks with the most appropriate option:-

Had the students studied properly, they ………… scored good marks in the exam.

would have

The correct option to fill in the blanks is would have.

The sentence is about a hypothetical situation in which the students studied properly and scored good marks in the exam. The past perfect conditional tense is used to talk about hypothetical situations that did not happen. It is the most appropriate tense to use in this context, as it describes the condition that the students studied properly and the result that they would have scored good marks in the exam.

The other options are not as appropriate:

• Have is the present perfect tense. It is not accurate to use "have", as the students did not study properly and did not score good marks in the exam.
• Will have is the future perfect tense. It is not accurate to use "will have", as the students did not study properly and did not score good marks in the exam.
• Could have is the past perfect subjunctive. It is not as appropriate as "would have", as it does not convey the same sense of certainty or likelihood.