Agroup of astronomers observed light coming from a star located a distance of 331,000,000,000,000,000,000,000,000 light-years from earth. what is this distance expressed in scientific notation?

a.
3.31 × 1026 light-years
b.
3.31 × 10-26 light-years
c.
3.31 × 1024 light-years
d.
3.31 × 10-24 light-years
e.
3.31 × 1025 light-years