There is a group of words below that belong to pictophonetic characters. Please find them. A Yu Xia's body B saw the mold fork shower C spectrum was shoveled by a good hedgehog D crystal.

B, fork-known word (where the mountain forks)

C, considerate words (Xiao Zhuan, like a horn, from "North". From the "north", take the meaning of cracking the back. Original meaning: deviation, violation, disharmony)

D, crystal-knowing word (Oracle Bone Inscriptions glyph, from three days, indicating the meaning of light. Original meaning: bright, bright)

Only a is a full-tone character.

Bang (external sound) summer (left shape and right sound) in (upper shape and lower sound) body (left shape and right sound)