Question

Which graph represents y as a function of x?
Responses
A
A circular shape is centered at the origin on a grid with both x and y axes marked from -4 to 4. The circle's outline intersects the axes, creating symmetry around the center.
Image with description A circular shape is centered at the origin on a grid with both x and y axes marked from -4 to 4. The circle's outline intersects the axes, creating symmetry around the center.
C
A two-dimensional grid with horizontal and vertical axes marked x and y. A bold curve is shown, starting at the top-left quadrant of the grid and moving downward and rightward to the negative side of both axes, forming a rough arc shape.
Image with description A two-dimensional grid with horizontal and vertical axes marked x and y. A bold curve is shown, starting at the top-left quadrant of the grid and moving downward and rightward to the negative side of both axes, forming a rough arc shape.
B
A grid with x and y axes shows a curve that starts at the left, moves upward, and then curves downward to the right.
Image with description A grid with x and y axes shows a curve that starts at the left, moves upward, and then curves downward to the right.
D
A coordinate plane showing a semi-circular curve. The curve extends from the point on the x-axis at positive 4 to the same y-value and returns to negative 4 on the y-axis. The origin is unmarked by the curve, maintaining symmetry about both axes.
Image with description A coordinate plane showing a semi-circular curve. The curve extends from the point on the x-axis at positive 4 to the same y-value and returns to negative 4 on the y-axis. The origin is unmarked by the curve, maintaining symmetry about both axes.

Answer 1

B

Reason: The graph in B passes the vertical line test (each x-value has exactly one y-value). A (circle) fails the test. C and D as described would give some x-values with more than one y.