The answer is choice D-All of these :)
I am not too familiar with the Python language, but the algorithm would be something like this:
1. create a variable for the sums of the number
2. read in how many numbers the user wants to enter (let's call it N)
and then create a for loop:
for N times
read in the next number
increase the sum variable by that number
Hopefully this helps!
Google Analytics, this is a common one but there are others that do the same thing.