Which approach is the least effective way to involve parents in library programs?

The choice of using keywords like "or," "but," and "and" as a method for involving parents in library programs is the least effective approach because it lacks a direct and actionable strategy to engage parents. This option does not represent a tangible method for interaction or involvement; rather, it refers to a grammatical structure that has no direct relation to participation in library activities.

In contrast, inviting parents to attend events directly encourages their presence and participation, creating opportunities for them to engage with the library and community. Offering virtual sessions is also an effective way to reach parents who may not be able to attend in-person events due to time constraints or other reasons, thus broadening access and involvement. Sending home flyers is another common practice that allows parents to be informed about library programs and events, fostering their awareness and potential participation.

Thus, the correct choice reflects a more passive method that does not facilitate direct involvement compared to the more proactive and accessible strategies represented by the other options.