2 C's are connected with a single line, and each has an H attached by a single line above, below, and outside.
B
2 C's are connected with 2 parallel lines. There are H's connected with single lines above left, above right, below right, and below left of the 2 C's.
C
A C is connected to an O with 2 parallel vertical lines, and below left to H with a single line and below right to O H with a single line.
D
2 C's are connected by 3 parallel lines. There is an H connected with a single line to the left and to the right.