Two stations $A$ and $B$ are $100 \mathrm{~km}$ apart on a straight line. One train starts from $A$ at 7 A.M. and travels towards $B$ at $20 \mathrm{~km} / \mathrm{hr}$ speed. Another train starts from $B$ at 8 A.M. and travels towards $A$ at $25 \mathrm{~km} / \mathrm{hr}$ speed. At what time will they meet?
(a) 10.30 A.M.
(b) 11 A.M.
(c) 10 A.M.
(d) None of these