When two lines intersect and they make a 90 degrees angle between them, then those lines are said to be perpendicular to each-other and all four angles between them are 90 degrees each.
In the given diagram we can see that two lines are intersecting and angle ∠2 is marked as 90 degrees. It means these two lines are perpendicular to each other and all angles would be Right angles i.e. 90 degrees each.
Hence ∠1 ≅ ∠2 = 90°
Hence, option B is correct.