Which of the following is not the correct formula for base pitch?

• A. Base circumference / Number of teeth
• B. ‚âà√¨‚àö√ë x Base circle diameter / N
• C. ‚âà√¨‚àö√ë x D sin‚âà√¨‚àö√∫ / N
• D. ‚âà√¨‚àö√ë x m x cos‚âà√¨‚àö√∫