Momma's horrible snake-woman voice came out again and said, 'If you ever, ever . . . '
A metaphor is a comparison of two things without using like or as. In this sentence Momma's voice is being compared to that of a snake-woman. It is showing her disappointment in whatever her child did. The other options are all similes. They compare two things, just like a metaphor, but they use the word "like" which is indicative of a simile.