The correct option is B quarter to 7
Half - past 6 = 6 : 30
After 15 mins, the time will be 6 : 45.
An hour has 60 mins.
So, when the time is 6:45, there is (60 - 45) mins =15 mins left to complete the hour.
i.e., a quarter is left to an hour.
So, 6 : 45 can be read as quarter to 7 because after 15 more minutes, the time will be 7 : 00.