Read the lyric and answer the following questions.

Firework
By Katy Perry

Do you ever feel like a plastic bag
Drifting through the wind, wanting to start again?
Do you ever feel, feel so paper thin
Like a house of cards, one blow from cavin' in?
Do you ever feel already buried deep?
Six feet under screams, but no one seems to hear a thing
Do you know that there's still a chance for you?
'Cause there's a spark in you

You just gotta ignite the light, And let it shine 
Just own the night, Like the Fourth of July

'Cause baby, you're a firework, Come on, show 'em what you're worth
Make 'em go, "Oh, oh, oh", As you shoot across the sky
Baby, you're a firework, Come on, let your colors burst
Make 'em go, "Oh, oh, oh", You're gonna leave 'em all in awe, awe, awe
You don't have to feel like a waste of space

You're original, cannot be replaced
If you only knew what the future holds
After a hurricane comes a rainbow
Maybe a reason why all the doors are closed
So you could open one that leads you to the perfect road
Like a lightning bolt, your heart will glow
And when it's time, you'll know

You just gotta ignite the light, And let it shine
Just own the night, Like the Fourth of July

'Cause baby, you're a firework
Come on, show 'em what you're worth
Make 'em go, "Oh, oh, oh" As you shoot across the sky
Baby, you're a firework Come on, let your colors burst
Make 'em go, "Oh, oh, oh"
You're gonna leave 'em all in awe, awe, awe

Boom, boom, boom, Even brighter than the moon, moon, moon
It's always been inside of you, you, you, And now it's time to let it through

'Cause baby, you're a firework 
Come on, show 'em what you're worth
Make 'em go, "Oh, oh, oh"
As you shoot across the sky, Baby, you're a firework

Come on, let your colors burst Make 'em go, "Oh, oh, oh
You're gonna leave 'em all in awe, awe, awe
Boom, boom, boom Even brighter than the moon, moon, moon
Boom, boom, boom Even brighter than the moon, moon, moon

 (source: https://www.google.com)

b. What does the word "you" in the sentence "Cause baby, you're a firework" refer to in the song?