The working depth of a gear is radical distance from the
(a) pitch circle to the bottom of a tooth
(b) pitch circle to the top of a tooth
(c) top of a tooth to the bottom of a tooth
(d) addendum circle to the clearance circle
The question was asked in an internship interview.
My query is from Law of Gearing-1 in chapter Toothed Gearing & Gear Trains of Machine Kinematics