Choose the most appropriate passive construction/s from the options g…

The correct answer is Option (1) → (A) and (C) only

Passive voice of a verb with two objects (simple present):

• "Teach" here has two objects: us (the person) and grammar (the thing). Either object can become the subject of the passive sentence.
• Object becomes subject: either the thing "grammar" (Grammar is taught to us ...) or the person "us", which becomes "we" (We are taught grammar ...).
• Tense kept: be + past participle in the same tense; the simple present "teaches" → "is taught" (grammar) or "are taught" (we).
• Other tenses: was/were + V3 (simple past), is/are being + V3 (present continuous), has/have been + V3 (present perfect), will be + V3 (simple future).
• Agent (by ...): the doer "Mr. Parashar" goes after the verb with "by".
  Example: The coach gives them advice. → They are given advice by the coach.

(A) Grammar is taught to us by Mr. Parashar. — Correct. The thing object "grammar" is the subject, "is taught" keeps the simple present, and the person object follows as "to us".

(B) Grammar has been taught to us by Mr. Parashar. — Incorrect. "Has been taught" is the present perfect; the tense of "teaches" (simple present) is not kept.
Correct form: Grammar is taught to us by Mr. Parashar.

(C) We are taught grammar by Mr. Parashar. — Correct. The person object "us" becomes the subject "we", with "are taught" in the simple present.

(D) We have taught grammar by Mr. Parashar. — Incorrect. "Have taught" is an active verb (present perfect) with no form of "be"; the sentence is not passive and makes no sense with "by Mr. Parashar".
Correct form: We are taught grammar by Mr. Parashar.