Answer: The word that could be substituted for "invest" to express a neutral viewpoint is D. take.
Explanation: In the case of this sentence, the word "take" would be functioning as a verb. Moreover, when "take" is used with a phrase that indicates time reference such as "an hour", it means to devote some time to an activity. "Take" is a neutral word because it is not associated with a good or bad feeling. In contrast, the word "enjoy" has a positive connotation, which means that it suggests a positive idea, while "lose" and "waste" express negative feelings. In that way, "enjoy", "lose" and "waste" cannot be considered neutral words.