Hello!
The answer is:
The correct option is the first option, the average speed in blocks per minute is 1.5 blocks per minute.

Why?
To calculate the average speed we need to calculate the total distance traveled and the total time taken to cover that distance.
From the statement we know that:

So, we need to use the following formula in order to calculate the average speed:

Then, substituting we have:


Hence, we have that the correct option is the first option, the average speed in blocks per minute is 1.5 blocks per minute.

Have a nice day!