At which Sun–Earth Lagrange point does the Aditya-L1 satellite observe the Sun?

Concept — Lagrange points. For any two bodies in mutual orbit, such as the Sun and the Earth, there are five special positions at which the combined gravitational pull of the two bodies supplies exactly the centripetal force a much lighter third body needs in order to circle the Sun with the same orbital period as the Earth. A spacecraft placed near one of these five points therefore keeps a fixed geometry with respect to both bodies and can hold station there on very little fuel. Which of the five is chosen is what decides what the spacecraft is able to keep in view without interruption.

Applying it to this mission. Aditya-L1 is ISRO's first dedicated solar observatory. It was launched on 2 September 2023 and was inserted on 6 January 2024 into a halo orbit around the Sun–Earth L1 point, about 1.5 million km from the Earth in the direction of the Sun. Because that point lies on the Sun-facing side of the Earth, the solar disc as seen from there is never blocked by the Earth or the Moon, so the imaging payloads can watch the photosphere, chromosphere and corona continuously, while the in-situ instruments sample the solar wind and the interplanetary magnetic field roughly an hour before that material reaches the Earth. The Sun observation point of Aditya-L1 is therefore L1 — the very point the mission is named after.

Comparing the three Lagrange points named in the choices.

Cross-check. L1 and L2 are both about 1.5 million km from the Earth, so distance alone does not separate them; it is the direction that does. An uninterrupted view of the solar disc is available only from the Sun-facing side, and that is the L1 station. Because a single such station is named, neither a combination of the listed points nor a location outside the list describes where Aditya-L1 observes the Sun from.