Write the next sentence in this paragraph:

How to ride the mbta subway in massachusetts
Learn the different train colors and study a map.
Within the system, there are red, green, orange, blue, and silver lines. The silver line is more of an articulated bus rather than an underground subway.

Pick your answer from:
(a). Some lines intersect with each other in the boston metropolis or major station depots (such as the north and south stations) and then weave out to different parts of the city. In addition, there are commuter rails that run in & out of boston, as well as many bus lines run around other cities that connect with subway lines.
(b). Their colors, generally, turn out neon and anything physically functional is yellow. Once you are on the subway, recognize that there is a conductor as the ticket pick person who will give the ticket to you.
(c). The green line corresponds to the color of a flag, so if you ride a green or red train, the color probably matches yours. The train may have a blue car or a green circle in the middle so you would forget which direction to go.
(d). Refer to the map for prelooks. Enter the subway app on your phone.
(a).