Which of the following best describes formative assessment?

Formative assessment is best described as an ongoing process to monitor student learning. This type of assessment is integrated into the learning process and is used by educators to gather information about student understanding and skills while instruction is still taking place. The key characteristic of formative assessment is its responsiveness; it enables teachers to identify areas where students may be struggling and adjust their teaching strategies accordingly. This ongoing feedback loop promotes a better understanding of content and helps improve learning outcomes.

In contrast, the other options represent different assessment approaches. Evaluating learning at the conclusion of a unit pertains to summative assessment, which measures student learning after instruction has been completed. Summative assessment typically provides a snapshot of what students have learned and is often used for assigning final grades. Similarly, a rigid assessment that does not allow for adjustments suggests a lack of flexibility and responsiveness, which is counter to the nature of formative assessment. Thus, option B captures the essence of formative assessment by highlighting its ongoing and adaptive characteristics in the learning environment.