Given two normalized wavefunctions of a molecule, ${ f }_{ 1 }$ and ${ f }_{ 2}$, are described by different symmetry labels under the point group of the molecule, which statement below is TRUE?

A

The integral of the product of ${ f }_{ 1 }$ and ${ f }_{ 2}$ cannot be determined.

B

The integral of the product of ${ f }_{ 1 }$ and ${ f }_{ 2}$ will be zero.

C

The integral of the product of ${ f }_{ 1 }$ and ${ f }_{ 2}$ will not be zero.