The Normalized Wave Function for a Hydrogen Atom in the 1s

The normalized wave function for a hydrogen atom in the 1s state is given by ψ(r) = e^-r/α₀ where α₀ is the Bohr radius,which is equal to 5.29 × 10^-11 m.What is the probability of finding the electron at a distance greater than 7.8 α₀ from the proton?

A) 2.3 × 10^-5
B) 1.2 × 10^-5
C) 1.7 × 10^-5
D) 4.6 × 10^-5
E) 3.5 × 10^-5