What type of figurlative laanguage is belch in this sentence

annie heard the old locomotive belch and she felt a lurch. the wheels began to shriek as they rolled slowly forward along the shining rails. annie waved her lace hanky from the window until she could no longer see her parents. what an adventure to be off for her new life as a nanny to four young baker children.

a.
onomatopoeia

b.
simile

c.
metaphor