Make your life easy!
Two choices for you to adopt:
The first method:
If partition E is next partition C, you may do like this:
If partition E is next partition C with a lot of unused space in it, you can merge these two partitions (Before merging these two partitions, you can transfer all data in partition E to other place by EaseUS Partition Master copy function):
1. Right click partition C and choose "Merge partition"2. Then choose partition E to be merged into partition C. Then click OK and apply this change and you will get an enlarged partition C by merging two adjacent partitions.
If the partition E is not next to partition C but after partition D, please move the space to partition D, then move to partition C, following the method above step by step.
The second method:
You can get an extended partition C by "Resize/Move partition" function.
First, shrink the data partition right behind the partition C.
After you get the unallocated space, make it just set behind the C drive by Resize/Move partition functions so that you can enlarge the partition C by redistributing the unallocated space.