Select the option that expresses the given sentence in passive voice.

The secretary was noting down the dictation.

The dictation was being noted down by the secretary.

The correct passive voice form of the given sentence "The secretary was noting down the dictation" is The dictation was being noted down by the secretary.

The active voice of the sentence is "The secretary was noting down the dictation." This sentence is in the present progressive tense, which is used to describe an action that is happening now but is not finished. The passive voice of the sentence is formed by putting the subject of the active sentence after the verb "to be" and the present participle of the main verb. In this case, the subject of the active sentence is "secretary" and the main verb is "note." The past participle of "note" is "noted." So, the passive form of the sentence is "The dictation was being noted down by the secretary."

The other options are incorrect because:

• The secretary noted the dictation." This sentence is in the simple past tense, which is used to describe an action that happened in the past. However, the action of noting down the dictation is still happening.
• The dictation was noted down by the secretary." This sentence is in the simple past tense, but the verb is in the wrong form. The correct form is "being noted down."
• The notes were noted by the secretary." This sentence is incorrect because the subject of the sentence is "notes," which is plural. However, the verb "note" is singular.
• The dictation were noted by the secretary." This sentence is incorrect because the verb "note" is singular. The subject of the sentence must also be singular.