Which is the first and biggest asteroid discovered?
(A) Vesta
(B) Titan
(C) Ceres
(D) Charon

Hint: In order to answer this question, to know the name of the first and biggest asteroid discovered till now, first we will mention the asteroid name which is the first and biggest. And then we will discuss that asteroid in brief.

Complete step-by-step solution:
Giuseppe Piazzi, an Italian priest and astronomer, accidently found Ceres, the first and largest asteroid, orbiting between Mars and Jupiter, while drawing a star map in 1801.
Ceres is the largest asteroid in the main asteroid belt, which lies between Mars and Jupiter's orbits. It makes up a fifth of the belt's mass and is the only asteroid large enough to be rounded by its own gravity, despite Vesta and maybe other asteroids being able to do so in the past. Ceres is the smallest dwarf planet known, as well as the only one within Neptune's orbit.
Ceres, the first known asteroid, was discovered on January 1, 1801 at the Palermo Astronomical Observatory by Giuseppe Piazzi. It was once thought to be a planet, but after numerous more objects in similar orbits were discovered in the 1850s, it was reclassified as an asteroid. It has now been classed as a C-type asteroid as well as a G-type asteroid due to the presence of clay materials.
Ceres appears to be partially separated into a muddy (ice-rock) mantle/core and a less dense but stronger crust that is at most 30% ice. Water ice and other hydrated minerals like carbonates and clay make up the surface. Cryovolcanoes like Ahuna Mons only appear once every fifty million years or so. Water vapour emissions were reported in various locations of Ceres in January 2014. This was surprising because huge asteroids in the asteroid belt don't usually produce vapour, which is a characteristic of comets. The atmosphere, on the other hand, is impermanent and of the exosphere kind.
Hence, the correct option is (C) Ceres.

Note:31 Euphrosyne — Euphrosyne is the darkest of the nearly 30 asteroids known from the belt. It's a C-type asteroid that orbits towards the edge of the belt and has a large mass, making it solid rather than porous.