_ The unit of filter medium resistance is$?

• A. Cm‚Äö√Ö¬™¬¨œÄ
• B. Gm/cm‚Äö√Ö¬™¬¨œÄ
• C. Cm/gm‚Äö√Ö¬™¬¨œÄ
• D. Gm‚Äö√Ö¬™¬¨œÄ