Final answer:
Bottled water is a good idea because it is convenient and easy to carry. Therefore, the correct option is C.
Step-by-step explanation:
The reason that best supports the opinion that bottled water is a good idea is option C: Bottled water is convenient and easy to carry. This reason highlights the practicality and portability of bottled water, making it a popular choice for people on the go or in situations where access to tap water is limited.