Which principle of adult learning is beneficial for teachers in professional development?

C is the most beneficial principle of adult learning for teachers in professional development because involving adults in planning the instruction acknowledges their existing knowledge, experiences, and skills. Adult learners bring a wealth of personal and professional backgrounds to the table, which can greatly enhance the learning process. When they actively participate in the planning stages, they are more likely to engage with the content, as it relates directly to their needs and interests. This can lead to more meaningful and effective professional development experiences, fostering a collaborative environment where teachers feel valued and empowered.

The other options, while they may appear relevant, do not hold the same level of significance in terms of fostering effective learning. Required participation can lead to resentment and disengagement, as adults often thrive in environments where they feel they have a choice. Conversely, simply providing learning materials without input from the learners may not address their specific contexts or challenges. Finally, while informed assessments are helpful, they are secondary to the active involvement of learners in the planning process, which fundamentally enhances ownership and relevance in their professional growth.