The correct option is B can be considered approximately parallel.
Nope, sunrays are not exactly parallel. And no, we don't just randomly assume it to make problems and life easy! Rather, it is a good approximation to consider sunrays to be parallel when they reach us, as the sun is really really far (149.6 million km!) from the Earth, hence the angle between the rays are very very small. Go watch the video again to realize this.