Answer:
B.

Explanation:
We have been given coordinate of a point (4,7). We are asked to find the equation of the line that has an undefined slope and passes through the given point.
We know that slope of a vertical line is undefined. So the vertical line passing through point (4,7) will have an undefined slope.
The slope of line will be undefined when x-coordinates of all points on the line are equal.
Since the line
will have same x-coordinates for all y-coordinates, therefore, option B is the correct choice.