In a conference, a track, session, workshop, and certificate are chosen. In the normal (3) tracks there are (6) sessions, (5) workshops, and (2) certificate options; in the fourth track there are (3) sessions, (5) workshops, and no certificate option. How many selections are possible?

Correct answer: (195)

Direct answer: option C, 195 selections. Use the fundamental principle of counting: when one choice is made after another, multiply the numbers of choices. For any of the three normal tracks, there are 6 session choices, 5 workshop choices, and 2 certificate choices, so the number is 3 × 6 × 5 × 2 = 180. In the fourth track, there are 3 sessions and 5 workshops, but no certificate choice; therefore it gives 3 × 5 = 15 selections. The cases are separate, so add them: 180 + 15 = 195. Option A, 210, is wrong because it does not use the correct total. Option B, 180, counts only the normal tracks and ignores the fourth track. Option C is correct because it includes both cases. Option D, 165, also results from an incorrect calculation. Memory cue: multiply within one case and add separate cases.