You did not include the graphs, but I can explain how the graph is and so you can recognize it.
1) for x = 0, y = sin(0) = 0, so the origin (0,0) is part of the graph.
2) The range of the function is the interval [-1, 1]. This is, y is from -1 to 1, and the graph oscilates (is a wave) between those minimum and maximum.
3) The periodicity, P, of the function is such that 0.5P = 2π = > P = 4π
That means that the values repeat every 4π interval (which is the same that 720°)
4) The zeroes of the function are 2π * n, where n is any whole number (negative, zero or positive).
That means that the function crosses the x-axis at
..., -6π, -4π, 2π, 0, 2π, 4π , 6π, ...
5) It is an odd function (which means that f(x) = sin(0.5x) = - f(-x) = - sin(-0.5x).
Now you have plenty information to identify the graph.
I also include a graph of the function in the attached pdf file.
