Select the correct passive form of the given sentence.

Special buses will ferry students to their colleges.

Students will be ferried to their colleges in special buses.

The correct passive form of the given sentence is Students will be ferried to their colleges in special buses.

The other options are incorrect because:

• Students are to be ferried to their colleges in special buses uses the modal verb "to be" to express obligation, but it is not used correctly in the passive voice.
• Students had been ferried to their colleges in special buses uses the past perfect tense, while the original sentence is in the future tense.
• Students are being ferried to their colleges in special buses uses the present progressive tense, which is not typically used for actions that happen in the future.
• Students will ferry to their colleges in special buses is in the active voice, not the passive voice.