Read the following context and choose the best option to answer the question.
Context: She was my unicorn , as Alexa would say - the perfect one you would have been happy forever with , but could never have . And when I realized that it was never going to work out like we ... I had dreamed it would , I was crushed .
Question: What is his definition of a unicorn ?
Options: 
- Something that was perfect , but could n't be possessed .
 - None of the above choices .
 - Alexa was definately his definition of a perfect unicorn .
 - A dream that would make you happy forever .


Something that was perfect , but could n't be possessed .