The correct answer is (d).
The total production of Type-T scooters in 2016 was 2 lakhs, in 2017 was 3 lakhs, in 2018 was 4 lakhs, and in 2020 was 5 lakhs. Therefore, the only pair of years in which the total production of Type-T scooters was three lakhs is 2017 and 2020.
(a) 2016 and 2018: The total production of Type-T scooters in 2016 was 2 lakhs, and in 2018 was 4 lakhs. Therefore, the total production of Type-T scooters in 2016 and 2018 was 6 lakhs, which is not equal to three lakhs.
(b) 2018 and 2020: The total production of Type-T scooters in 2018 was 4 lakhs, and in 2020 was 5 lakhs. Therefore, the total production of Type-T scooters in 2018 and 2020 is 9 lakhs, which is not equal to three lakhs.
(c) 2017 and 2020: The total production of Type-T scooters in 2017 was 3 lakhs, and in 2020 was 5 lakhs. Therefore, the total production of Type-T scooters in 2017 and 2020 is 8 lakhs, which is not equal to three lakhs.