Answer/Explanation:
"f" is perpendicular to "c". We know that "f" is perpendicular to "d", meaning "f" is at exactly 90° to "d". "c" is parallel to "d", which means are lines that will never meet.
The parallel lines "c" and "d" are also tilted to be at the same angle in relation to "f". This means that "f" is also at exactly 90° to "c", so "f" is perpendicular to "c".
