A clock is set right at 8 AM. This clock gains 10 minutes in 24 hours.
What is the true time when the clock indicates 11 AM ?

The clock gains a total of 10 min in 24 hours. 

So, in 3 hours, the clock will gain a total of $$\dfrac{10\times3}{24}=\dfrac{10}{8}=1\dfrac{1}{4}$$ min 

When the clock indicates a time of 11 am, after it started at 8 am, it has gained a total of $$1\dfrac{1}{4}$$ min. 

The true time can be found by subtracting the time gained from the actual time indicating by the clock. 

So, we have to subtract 1 min and 15 seconds from 11 am to find the true time. 

Hence, the true time is 10:58:45 am. 

Option D.