Final answer:
The unit rate for cross stitching is 1 row per 0.5 minutes.
Step-by-step explanation:
The unit rate for cross stitching can be found by dividing the number of rows stitched by the amount of time taken. We need to find the option that represents 1 row per the least amount of time. Comparing the given options, we can see that option D) 1 row per 0.5 minutes represents the fastest rate of stitching. Therefore, the correct answer is D) 1 row per 0.5 minutes.