💡 Detailed Explanation
The correct choice is Option 3: 'Because the hotel's hot spring machine is broken and the bath cannot be used.' The wife explains: '温泉の給湯機械の故障で、週末はお風呂が使えないんだって' (Due to a failure in the hot spring water heating machine, the bath cannot be used this weekend). Weather (Option 1) is fine, and work or illness are not mentioned. Thus, Option 3 is correct.