It would be appropriate to consider a sports drink instead of water primarily when engaging in prolonged or high-intensity activities that last longer than 60 minutes, especially when there is a significant loss of electrolytes through sweat.
Based on your options, none of the activities listed (lifting heavy weights for 30 minutes, running for less than 20 minutes, doing crunches and sit-ups for 15 minutes, or walking for less than 45 minutes) would typically warrant the use of a sports drink instead of water. For these shorter durations, water is generally sufficient for rehydration.
Therefore, none of the provided responses would be appropriate for choosing a sports drink over water.