Which sentence uses a simile?

 - Her laughter was like a bird's song.
 - Her laughter was a bird's song.
This sentence uses a simile:
Her laughter was like a bird's song.
The words laughter and bird's song are compared using the word like.
This sentence uses a metaphor:
Her laughter was a bird's song.
The words laughter and bird's song are compared without the word like or as.