how to extend drive c in windows 8

1. kat dahlia i think i鈥檓 in love I'm using Windows 8 1 It is installed on the C: drive The problem is that the drive is full I have 200 GB of unallocated space, but I don't know how to merge it with the C: drive I tried to extend the drive from My Computer → Manage but that option is not available there: These are my drives: