choice C is correct because when data from both statements is provided (that is the coordinates of both the points) it can be possible to determine the lengths of both the lines.

since it is given that QR is parallel to the y-axis and PR is parallel to x-axis, we can find the coordinates of point R.

the x coordinate for R will be the same as that of Q (which is point c)

and the y coordinate will be the same as that of P (which is point b)

therefore coordinates of R will be (c,b)

now in order to calculate the length of QR, we need the y coordinates of both Q and R.. that is points d and b.

(the x coordinates are not necessary since we know that the line is parallel to the y axis.)

similarly, to calculate the length of PR, we need the x coordinates of both P and R.. that is points a and c.

(the y coordinates are not necessary because we know that the line is parallel to x axis.)

thus if we know the numerical value of the points represented by a,b,c and d, we can find the lengths of both the lines (QR and PR).

now, if we know the lengths of both the lines, we can easily find the ratio and see whether or not it will be equal to 1.

if there is any particular statement in my explanation where you loose the flow or cannot understand, just let me know!

hope this helps!

cheers!

_________________

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