Do the math
At first glance, you might assume that a 20-in. by 24-in. window (A) would be acceptable for egress. Those dimensions would yield a net clear opening of only 3.3 sq. ft.
To achieve the required net clear opening of 5.7 sq. ft., a 20-in. wide window (B) would have to be 42 in. high.
Likewise, a 24-in. high window (C) would have to be 35 in. wide.