To determine the correct substitution for the underlined segment "Rohit is write," we need to focus on the verb tense that accurately reflects the action in the sentence. The sentence likely intends to convey an action that has occurred at least once in the recent past, therefore requiring the present perfect tense.

The present perfect tense is formed with "has" or "have" followed by the past participle of the verb. In this case, the verb "write" needs to be converted to its past participle form, which is "written."

The options provided are:

• Rohit had write
• Rohit has written
• Rohit was beings written
• Rohit was write

Let's evaluate them:

• Rohit had write: Incorrect. "Had" is used for past perfect tense, which does not match the intended meaning. Moreover, "write" is incorrect as it should be the past participle "written."
• Rohit has written: Correct. This option uses "has" for present perfect tense and "written" as the past participle, accurately conveying "Rohit has written to them three times."
• Rohit was beings written: Incorrect. This option is grammatically incorrect as "was beings" is not a valid verb form.
• Rohit was write: Incorrect. The verb form "was write" is incorrect because it does not use the past participle form, nor is it an appropriate past tense.

Thus, the correct answer is "Rohit has written."