​This type of disk enables you to write onto it in multiple sessions

A) ​CD-R
B) ​CD-RW
C) ​DVD+R and DVD-R
D) ​External hard drive
E) ​USB flash drive

CD-RW

Compact Disc-ReWritable, a type of CD disc that allows users to write, erase, and rewrite data multiple times.

DVD+R

A recordable DVD format with a storage capacity of 4.7 GB, allowing users to write data to the disc once.

External Hard Drive

A portable storage device used for backing up data from a computer or transferring files between computers, and is external to the internal hard drive.