System Software, Architecture, Memory and Storage Practice Test

The main idea here is that optical discs have a limited storage capacity, which makes them a less capable option for large data sets. A standard CD holds about 700 MB, and a typical single-layer DVD holds around 4.7 GB. Even though dual-layer DVDs offer more, the capacity is still small compared with modern hard drives or USB flash drives. This fixed, relatively low capacity is the core drawback when you need to store large amounts of data, big video libraries, or many files.

That’s why low capacity is the best answer. The other statements describe advantages that optical discs don’t provide: high capacity would contradict the limitation described, being durable and scratch-resistant isn’t accurate since discs can be damaged by scratches, and read/write speeds on optical discs are not very fast compared with other storage media.