Which subway line do you take from Penn Station to 23rd Street in Manhattan?

There are several subway lines that stop at 23rd Street in Manhattan. From west to east, they are the:

C and E trains (of the A-C-E, the blue line) at West 23rd Street and 8th Avenue

1 train (of the 1-2-3, the red line) at West 23rd Street and 7th Avenue

F or M trains (of the B-D-F-M, the orange line) at West 23rd Street and 6th Avenue

N, R or W trains (of the N-R-Q-W, the yellow line) at East 23rd Street and Broadway

6 train (of the 4-5-6, the dark green line) at East 23rd Street and Lexington

See the Related Link below for a complete New York City subway map.