Sorry, AC....I saw the first one yesterday....but I don't know what the "2.5" represents....maybe someone else knows....!!!!
However.....all is not lost....!!!!.....here's my answer to the second one :
Since this is an exponential growth, I probably means the number of people who started the challenge, B.
This is because as it is growing, the is exponentially growing of the the beginning variable, or the number of people in the beginning.
Sorry it's a bad explanation but I'm pretty sure the answer is B.
Do you guys understand my response?