Decrypt the aes-encrypted key with the aes-key and iv:
openssl enc -d -aes-256-cbc -in b-enc-aes.txt -out b-dec-aes.txt -K cddf0c7f664624fd0b604c622a2c670dffc3fdd7859a7cdd2377d1ba2ab86f89 -iv 30579741743af76bdd06ec45b12ee6d7

Decrypt encrypted file using the rsa private key
openssl pkeyutl -decrypt -inkey a1/c-rsa-priv.key -in a1/c-enc-rsa.txt -out a1/c-dec-rsa.txt

Verify the same files with the tool diff
diff plaintext.txt b-dec-aes.txt  -> Prints nothing, so its the same
diff plaintext.txt c-dec-rsa.txt  -> Prints nothing, so its the same