Correct answer: Option C — 12 seconds. 10 strikes contain 9 intervals, so one interval lasts 27/(9) = 3 seconds. 5 strikes contain 4 intervals, taking 12 seconds. Option A (13 seconds) is rejected because it does not equal the computed result; it represents a counting, direction, leap-year, interval, or hand-motion error. Option B (11 seconds) is rejected because it does not equal the computed result; it represents a counting, direction, leap-year, interval, or hand-motion error. Option D (14 seconds) is rejected because it does not equal the computed result; it represents a counting, direction, leap-year, interval, or hand-motion error.