Q: Start up shows two windows

After installing windows on my Macbook Pro 13'' 2015, the bootcamp installation didn't delete my windows iso installation partition drive.

When I press 'option' to select which partition to boot in start up, there are one Macintosh drive which is my os x and two windows partition.

The first one is the windows os and the other one just opens up the installation.

How can I delete the installation partition and give the space to windows partition?

Thanks!

By the way, when installing windows 10, I accidentally pressed the 'option' key after the setup finishes (it then goes to the boot menu) and then I select the windows partition to boot up windows. I don't know if that will cause an issue like this or not.