Select the option that best expresses the sentence in Indirect Speech…

The correct answer is Option (1) → The father asked his son why he had been crying the previous day.

Direct to indirect speech (question):

Change	Direct	Indirect	Why
Reporting verb	said to his son	asked his son	A question is reported with “asked”: “said to his son” becomes “asked his son”.
Joining word	“ ”	why	The question word “why” itself joins the clauses. No “that”.
Word order	were you crying	he had been crying	The question becomes a statement: subject + verb.
Pronoun change	you	he	“You” becomes “he”.
Tense change	were crying	had been crying	Past continuous “were crying” becomes past perfect continuous “had been crying”.
Words of nearness (time and place)	yesterday	the previous day	“Yesterday” becomes “the previous day”.
Full sentence	The father said to his son, “Why were you crying yesterday?”	The father asked his son why he had been crying the previous day.

Why the Other Options are Incorrect?

Option 2: The father asked his son that why he was crying the previous day. — Incorrect.

• "That" is not used with a question word like "why".
• The tense is not changed: "was crying" should be "had been crying".

Option 3: The father informed his son why he was crying the last day. — Incorrect.

• "Informed" turns a question into a statement of information.
• "The last day" is not the indirect form of "yesterday". The tense is also unchanged.

Option 4: The father asked his son why had been he crying the previous day. — Incorrect. It keeps the question word order (had been he). Indirect speech needs "he had been".