Final answer:
Comparing Bede's estimation to the actual northward length from the southernmost to the northernmost points of England, which is approximately 550 miles, would permit an estimate of the overestimation.
Step-by-step explanation:
The question pertains to the historical claim made by Bede about the northward extent of England from its southernmost point. To determine by how many miles Bede has overestimated this distance, we would need to know the actual length and compare it to Bede's claim. The southernmost point of England is Lizard Point in Cornwall, and the country extends northward to Marshall Meadows Bay, which is the northernmost point.
The actual distance is approximately 550 miles. Without Bede's exact figure, we can only speculate. However, if Bede's estimation was significantly greater than the actual distance, then one would choose the best fit among the options given: about 100 miles, about 250 miles, about 450 miles, or about 600 miles.