Select the option that expresses the given sentence in direct speech.…

The correct answer is Option (2) → Aryan said to his mother, “I paid the electricity bill online yesterday.”

Changing a statement from indirect back into direct speech:

Change	Indirect	Direct	Why
Reporting verb	told his mother	said to his mother	“Told” goes back to “said to” before the spoken words.
Joining word	that	“ ” (quotation marks)	“That” is dropped. Aryan’s own words go inside quotation marks.
Tense change	had paid	paid	“Had paid” is in the past perfect. The past perfect is formed with had + past participle (V3). Going back, it becomes the simple past “paid”, because the spoken words name a finished time, “yesterday”. The simple past is formed with the past form of the verb (V2).
Pronoun change	he	I	Aryan is the speaker and talks about himself. So “he” becomes “I”.
Time word	the previous day	yesterday	Aryan speaks of the day before he spoke. In his own words, “the previous day” becomes “yesterday”.
Full sentence	Aryan told his mother that he had paid the electricity bill online the previous day.	Aryan said to his mother, “I paid the electricity bill online yesterday.”

When there is no finished time word, had + V3 goes back to has / have + V3. Example: Rina said that she had lost her pen. → “I have lost my pen,” Rina said.

Why the Other Options are Incorrect?

Option 1: Aryan said to his mother, “I have paid the electricity bill online yesterday.” — Incorrect. “Have paid” is the present perfect. It cannot be used with a finished time like “yesterday”. The simple past “paid” is needed.

Option 3: Aryan said to his mother, “He paid the electricity bill online yesterday.” — Incorrect. “He” is not changed. Aryan speaks about himself, so it must be “I”.

Option 4: Aryan said to his mother, “I pay the electricity bill online yesterday.” — Incorrect. “Pay” is in the simple present. An action finished “yesterday” needs the simple past “paid”.