we know that
In parallelogram, the sum of consecutive angles are 180
so, consecutive angles are supplementary
And opposite angles are equal
so, we will check verify each options
option-A:
Since, consecutive angles are supplementary
so, this is FALSE
option-B:
Since, only opposite angles are equal or congruent
so, this is FALSE
option-C:
Since, consecutive angles are supplementary
so, this is TRUE
option-D:
Since, consecutive angles are supplementary
so, this is FALSE