The total energy of a particle is the sum of its kinetic energy and its potential energy. The zero of the potential energy can be chosen arbitrarily, so the potential energy can be negative. Classically forbidden regions are where...
a. a particle’s total energy is greater than its kinetic energy
b. a particle’s total energy is greater than its potential energy
c. a particle’s total energy is less than its kinetic energy.
d. a particle’s total energy is equal its potential energy
e. a particle’s total energy is less than its potential energy