The correct option is B
During a solar eclipse, the Moon's umbra covers only a small portion of Earth surface.
Lunar eclipses are more frequently visible because during a lunar eclipse, Earth casts a much bigger shadow on the Moon than the Moon casts during a solar eclipse on Earth. The reason solar eclipses are so rare is that the umbra of the Moon rarely hits the surface of the Earth. Even during a total solar eclipse, a small area on Earth is covered by the umbra.