This question tests your understanding of passive voice with modal verbs. Let's analyze the sentence structure:

The original sentence is: "You should give your baby Vitamin C." This is in active voice where "you" is the subject performing the action of giving.

The second part requires passive voice: "Vitamin C ought_____ to all babies." Here, Vitamin C is the subject receiving the action, so we need passive construction.

When using modal verbs like "ought to," "should," "must," or "can" in passive voice, the correct structure is:

Modal verb + be + past participle

For this specific case with "ought to":

$\mathrm{ought}\mathrm{to}\mathrm{be}\mathrm{given}$

Let's examine the options:

• "to give" - This is active voice, incorrect for this context
• "to be given" - This follows the correct passive structure with modal verb
• "given" - Missing the "to be" part required for passive voice
• "to given" - Grammatically incorrect construction

The complete correct sentence should be: "Vitamin C ought to be given to all babies."

Related Concepts

Passive Voice with Modal Verbs: When using modal verbs in passive constructions, always use the pattern: modal verb + be + past participle. Examples: "should be done," "must be completed," "can be seen."

Active vs. Passive Voice: In active voice, the subject performs the action. In passive voice, the subject receives the action. The passive voice is often used when the doer of the action is unknown or less important than the action itself.

Key Formula

Modal Passive Construction: Modal Verb + be + Past Participle