When the plane arrives in Toronto at 1:00 p.m, it's :

11:00 + 8:00 = 19:00 = 7 p.m. in Vienna

When it's 7 a.m. in Vienna, it's : 

7:00 - (7:00 - 1:00) = 1:00 (a.m.)

So, the answer is B

P/S : Dao Trong Luan's solution is quite illogical. I just redid it.

In Vietnam, the plane takes off at 11:00 and cost 8h for a plane of this type to fly this distance

=> In Vietnam when complete this distance is: 11:00 + 8:00 = 19:00

And this times in Toronto is 1:00

=> Time in Vietnam is faster than this in Toronto is18 hours

=> If Vietnam it is 7:00 => In Toronto is:

7:00 + 18:00 = 25:00 or 1:00 next morning

So choose B : 1:00 am

ansewrs 

(A) 1:00 pm