Answer:
B) 1.5 meters per second
Explanation:
The rate of change in Clara's speed between 10 and 60 seconds can be calculate as:

Where
is the mark at 60 seconds,
is the mark at10 seconds,
is the 60 seconds and
is 10 seconds.
Replacing values, we get:

So, the speed between 10 and 60 seconds is 1.5 meters per second