Someone give me the right answer!
the baldwin family walked four over five of a mile in four over nine of an hour. what is their unit rate in miles per hour?

a.) four-ninths over four-fifths equals four over nine miles per hour
b.) four-fifths over four-ninths equals one and four-fifths miles per hour
c.) four-ninths over four-fifths equals one and four-fifths miles per hour
d.) four-fifths over four-ninths equals four over nine miles per hour