Correct Answer: 3 and 4

Solution : Given:
9 × 3 ÷ 6 + 4 – 8 = 1

Replace the given numbers in the options one by one with the original numbers in the given equation.
Let's check each option –
First option: 8 and 9
9 × 3 ÷ 6 + 4 – 8 = 1
⇒ 8 × 3 ÷ 6 + 4 – 9
⇒ 8 × 0.5 + 4 – 9
⇒ 4 + 4 – 9 = 1
⇒ – 1 ≠ 1
Second option: 3 and 6
9 × 3 ÷ 6 + 4 – 8 = 1
⇒ 9 × 6 ÷ 3 + 4 – 8
⇒ 9 × 2 + 4 – 8
⇒ 18 + 4 – 8
⇒ 14 ≠ 1
Third option: 3 and 4
9 × 3 ÷ 6 + 4 – 8 = 1
⇒ 9 × 4 ÷ 6 + 3 – 8
⇒ 6 + 3 – 8
⇒ 1 = 1
Fourth option: 6 and 8
9 × 3 ÷ 6 + 4 – 8 = 1
⇒ 9 × 3 ÷ 8 + 4 – 6
⇒ 9 × 0.375 + 4 – 6
⇒ 1.375 ≠ 1

So, only the third option satisfies the equation. Hence, the third option is correct.