when people say " in lowest terms" they usually mean like the simplified version of an answer
an example of this would be like
make
into lowest terms
the answer would be 
if you dont understand comment on this and ill try to break it down more
im pretty sure that it is
i
Answer:A
Step-by-step explanation:
i have done it before
Two lines are perpendicular when the product between the slopes of the lines is equal to -1, then, if we have the following lines:

they will be perpendicular if,

According to the exercise, the first line is:

the slope for this line is -4.
Write the equation that makes two lines perpendicular,

solve for m2,

Answer:
The slope of the line perpendicular to y=-4x+7 is 1/4.