A rotating sprinkler waters the lawn outside the lodge at Oak Tree State Park. The sprinkler rotates in a full circular path and normally sprays water over a 4-meter radius. Due to a water main break near the park, the water pressure decreased slightly and the sprinkler only sprayed water over a 3-meter radius. How many square meters of lawn were not watered because of the decrease in water pressure? *

A, 5π square meters
B, 7π square meters
C, 9π square meters
D, 11π square meters