|Last time I read the diskpart documentation diskpart will not extend the system or boot partitions. This leaves only third party apps to do this.|
BTW Acronis is a clone utility which in the case of existing partitions would be useless.
The least risky expansion of c; is to backup and delete all other partitions, use PM or other to expand c: into the free space, recreate the old partitions in the remaining disk space and restore.
Otherwise you risk losing all of your data and having to start fresh with a wipe and repartition of the disk.