Statement I is incorrect. The corrected form of this statement is as follows:
Rishi went to a dentist yesterday.
In statement II, two past actions are described, where one action (the start of the play) occurred before the other (Farooq’s entry). In such cases, the past perfect tense is used.
The action that occurred before must be framed in the following way:
Had + Past participle form of verb
Had + Begun
The action that occurred later must be framed in the following way:
Past form of verb
Entered
So, statement II is correct.
In statement III, two past actions are described—Bobby and Pinky’s visit to Mauritius and Mani’s visit to the same place. The use of ‘before’ indicates that the former took place before the latter. However, the past perfect tense has not been used correctly.
The action that occurred before must be framed in the following way:
Had + Past participle form of verb
Had + Visited
The action that occurred later must be framed in the following way:
Past form of verb
Went
So, statement III is incorrect. The corrected form of this sentence is as follows:
Bobby and Pinky had visited Mauritius before Mani went there.
Hence, the correct answer is option D.