In order to extend the C drive, you will need to have contiguous space for it to expand into
from the looks of your second screenshot, the available space immediately after C is taken up by a extended partition with three logical partitions in it
If the free space AFTER this volume is what you intended to extend C into, you will need to use a partition management tool to move the logical volume to that empty part of the disk, so that the C drive can expand into the free space. You will also need to remove the currently formatted partition (it still looks to be formatted as an NTFS partition, albeit without a drive letter)
Could you go into a bit more detail as to what you are envisioning?
something like GParted or Easeus would help move things around a bit, but i would advice some familiarity with them before messing with your partition tables
Have you considered getting a second drive and cloning the data out to it?