Which statement about rhombuses and parallelograms is true?

A) Rhombuses ALWAYS have four equal sides; parallelograms sometimes do not.

B) Rhombuses ALWAYS have four right angles; parallelograms sometimes do not.

C) Parallelograms ALWAYS have opposite sides equal; rhombuses sometimes do not.

D) Parallelograms ALWAYS have opposite sides parallel; rhombuses sometimes do not.