Final answer:
The best activity for the student who has a 40th percentile in comprehension is using a plot chart to track the events in a story, as it directly helps in improving story structure understanding and sequence of events, thus aiding comprehension.
Step-by-step explanation:
When reviewing the student scores on a standardized reading test to identify the areas requiring additional instruction, we see that the student's lowest score is in comprehension, at the 40th percentile. Comparing this to the 75th percentile in vocabulary knowledge, 85th percentile in decoding, and 70th percentile in fluency, it's clear that comprehension is the primary area for improvement. The choice of activities should therefore focus on enhancing comprehension skills.
Among the given options, using a plot chart to track the events in a story is the most beneficial activity for this student. It directly addresses comprehension by helping the student organize and remember the plot details, which are key in understanding the structure and sequence of events within a text. This should contribute to improving the student's comprehension score.
Option A, or reviewing high-frequency words, is more suited to vocabulary development, which is less of a concern here. Option B, identifying context clues in sentences, could help with both vocabulary and comprehension, but it is less targeted towards story structure. Finally, Option C, listening to an audio version of the text, can support fluency and provide a different modality for experiencing text but does not require active engagement with the text's plot in the same way that a plot chart does.