Two identical adjacent rooms each have a light bulb operating at a brightness of 300 lumens. The bulb in one of the rooms is now replaced by a bulb with a higher brightness. What is the minimum brightness (in lumens) needed such that a user will notice the increased brightness as compared to the adjacent room (which is still at 300 lumens).
a.) 310
b.) 305
c.) 303.33
d.) 311.3