The base diameter of a conical helix is 80 mm. The angle between the base and slanting side is 60 degrees. Pitch of helix is 6 mm. What is the height of helix and number of revolutions?

• A. 69.2 mm, 12
• B. 39.2 mm, 6
• C. 30 mm, 7
• D. 80 mm, 12