Answer:
function b
Explanation:
When its asking for which function has a greater rate of change its asking for which slope has a greater value
the slope is calculated by change in y over change in x
for function a, as y goes up 2 x goes up 1
so the slope ( rate of change) is 2/1
for function b is y goes up 3 x goes up 1
so the slope (rate of change) is 3/1
3/1 is greater than 2/1 so function b has a greater rate of change