Step 1: Understanding the Concept
Urination (micturition) is controlled by two sphincters, the internal and the external urethral sphincter.
Step 2: Muscle Type
The external sphincter is made of skeletal muscle, which is striated.
Step 3: Nature of Control
Skeletal muscles are voluntary, so we can consciously hold or release urine.
Therefore it is skeletal and voluntary.
Final Answer:
The external urethral sphincter is made of skeletal muscle and is voluntary.
\[ \boxed{\text{(C) }\text{skeletal, voluntary}} \]