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

My father teaches students.

Students are taught by my father.

The correct option that expresses the given sentence in passive voice is Students are taught by my father.

The other options are incorrect because:

• My father is teaching students is in the active voice.
• Students are being taught by my father is grammatically correct, but it is in the present progressive tense, while the original sentence is in the simple present tense.
• A student is taught by my father is grammatically correct, but it implies that only one student is being taught by my father, while the original sentence does not specify the number of students.