The Rationale Underlying Portfolio Assessment Is That

The rationale underlying portfolio assessment is that:

A) multiple measures of performance over time provide a better indication of student strengths and weaknesses.
B) gathering multiple indicators of performance allows teachers more time to compile student report cards.
C) single tests to measure student achievement are more time- and cost-efficient than collecting achievement measures over time.
D) portfolio assessment has been found to be more reliable and valid than classroom-based tests.