The cycle time for each signal is twice the duration of its green light phase. The first signal has a cycle of 2 * 25 = 50 seconds. The second signal has a cycle of 2 * 39 = 78 seconds. The third signal has a cycle of 2 * 60 = 120 seconds. To find when they will all turn green simultaneously again, we need to find the Least Common Multiple (LCM) of their cycle times (50, 78, and 120 seconds). The LCM of 50, 78, and 120 is 3900 seconds. Converting 3900 seconds to minutes gives 3900 / 60 = 65 minutes. Since they all turned green at 2:00 pm, they will turn green together again after 65 minutes, which is at 3:05 pm. However, the question asks when they will *change* to green next. This implies the point in time when the transition happens. The question implies a period of green light and a period of red light. The signal turns green, stays green for a duration, then turns red, stays red for a duration, and then turns green again. The time given (25, 39, 60 seconds) is for green to red transition, and since green and red durations are the same, the full cycle is double these values. Therefore, the signal cycle durations are 50s, 78s, and 120s. We need to find the LCM of these cycle times: LCM(50, 78, 120) = 3900 seconds. 3900 seconds is equal to 65 minutes. If they all turn green at 2:00 PM, they will complete these cycles and be ready to turn green again after 65 minutes. Thus, they will simultaneously turn green again at 2:00 PM + 65 minutes = 3:05 PM. The options provided are in hours and minutes format. Let's re-evaluate the problem statement and options. The question states 'change colour from green to red'. This duration is given as 25, 39, and 60 seconds. Since the duration of green and red lights are the same, the total cycle time for each signal is twice the given duration. Signal 1 cycle: 2*25 = 50 seconds. Signal 2 cycle: 2*39 = 78 seconds. Signal 3 cycle: 2*60 = 120 seconds. We need to find the LCM of 50, 78, and 120. Prime factorization: 50 = 2 * 5^2, 78 = 2 * 3 * 13, 120 = 2^3 * 3 * 5. LCM = 2^3 * 3 * 5^2 * 13 = 8 * 3 * 25 * 13 = 24 * 25 * 13 = 600 * 13 = 7800 seconds. 7800 seconds / 60 = 130 minutes. 130 minutes = 2 hours and 10 minutes. Starting at 2:00 PM, adding 2 hours and 10 minutes brings us to 4:10 PM. This matches option B.