Math problem !!!

<p>Blue Book page 551 number15.
I sort of get why the answer is "a" but need confirmation if I'm thinking right... could someone give me their explanation?
thanks in advance. :)
ps. the problem is like the graph stuff (about hamster and practice etc...)</p>

<p>This type of problem requires you to look at the graph and analyze the variations of the data. In this case, the various times taken by the hamsters all fall in the same small band between 40 and 50. Also, there is no relation between the number of practices and the times. Hence, the function should not have p as a variable. </p>

<p>The only answer that EXCLUDES p is A.</p>

<p>thanks that's what i was thinking... :)</p>