Question 854762
The simple interest formula is:
{{{ A = P*( 1 + r*t ) }}}
They are saying {{{ A = f(t) }}}
That is just renaming it
{{{ f(t) = P + P*r*t }}}
------------------
The time in years, {{{ t }}} should be 
plotted on the horizontal axis
because it is the independent variable
( doesn't depend on anything else 
for it's value )
-------------------------------
{{{ P }}} is plotted on the vertical axis
From the data given, see what happens
when {{{ t = 0 }}}, which is the y-intercept
------------------------------------
10 times greater than zero is zero, so
the y-intercept is {{{ 2000 }}}
{{{ f(t) = 2000 + 10t }}}
So, the slope is {{{ 10 }}}
That makes the 2nd choice correct