What key characteristic differentiates structural unemployment from frictional unemployment?

• A. Structural unemployment is caused by economic cycles, while frictional unemployment is not.
• B. Structural unemployment is due to seasonal changes, while frictional unemployment is not.
• C. Structural unemployment involves a mismatch of skills, while frictional unemployment involves job transitions.
• D. Structural unemployment is temporary, while frictional unemployment is long-term.

Answer: (C)