The Rest Mass of a Proton Is 1

The rest mass of a proton is 1.0072764666 u and that of a neutron is 1.0086649158 u. The ⁴He nucleus weighs 4.002602 u. Calculate the mass defect of the nucleus in amu.

A) 0.029281 u
B) 1.98666 u
C) 2.6316 u
D) 0.001388 u
E) 0.058562 u