The surface area of ANY sphere ... EVERY sphere ... is
Area = (4 pi) x (radius)² .
All you have to do is take the radius, square it,
and multiply by 4 pi.
If you only know the diameter, the radius is half of it.
So for your sphere, the surface area is
(4 pi) x (1 unit)²
= (4 pi) x (1 square unit)
= 4 pi square units.