From the point on a bridge across a river, the angles of depressions of the banks on opposite sides of the river are 30∘ and 45∘, respectively. If the bridge is at a height of 3 m from the banks, find the width of the river.
a. 3(√3−1) m
b. 3(√3+1) m
c. (3+√3) m
d. (3−√3) m