A bag contains 5 gray tiles and 2 blue tiles. Jenny reached into the bag and picked a tile randomly, and then without replacing it, picked a second tile. If you know that she picked a blue tile with her first pick, what is the probability that she picked a gray tile with her second pick?
A1/6
B1/7
C5/6
D5/7
A1/6
B1/7
C5/6
D5/7