Which line has an undefined slope? a y = 0 b y = 2 c x = y d x = 2

Learn this :
VUX -- vertical line, undefined slope, represented by x = a number.
HOY -- horizontal line, 0 slope, represented by y = a number

so the line with the undefined slope is going to be  x = 2

I’m not positive but i think it’s none of your buisness