Why is 「微笑み選ぼう」 correct in grammar?


The sentence 微笑み選ぼう is part of the lyrics of a song called
[錆びついたマシンガンで今を撃ち抜こう](http://j-lyric.net/artist/a0039c4/l007405.html).

I'm wondering why it is correct in grammar because it seems to me that there
is supposed to be a を between 微笑み and 選ぼう.

== Update ==  
Here is the shorter version of the song for interpreting the meaning of this
sentence: [link](https://www.youtube.com/watch?v=HX9evhBKxf4).




It is omitted を. We often omit a post-positional particle especially in spoken
language.

For example, 本(を)買いに行く, 昨日(は),学校に行った, 明日どこ(へ)行く?, 何(を)食べようか?, etc.




It is omitted を. We often omit a post-positional particle especially in spoken
language.

For example, 本(を)買いに行く, 昨日(は),学校に行った, 明日どこ(へ)行く?, 何(を)食べようか?, etc.

