The expression for threshold voltage for the enhancement mode nMOSFET is:

• A. Φgc-2ϕf-Qbo/Cox-Qox/Cox
• B. Φgc+ϕf-Qbo/Cox
• C. Φgc-ϕf-Qbo/Cox+Qox/Cox
• D. Φgc+2ϕf-Qbo/Cox-Qox/Cox