Which of the following optical devices by default has the GREATEST storage capacity?

A standard single-layer DVD holds 4.7 GB, which is considerably less storage capacity than a Blu-Ray disc.

A DVD-R is a recordable version of a DVD and also holds 4.7 GB (single layer), not offering greater capacity than a Blu-Ray disc.

Blu-Ray discs significantly surpassed DVDs in storage capacity, with single-layer Blu-Ray discs typically holding 25 GB and dual-layer discs holding 50 GB, which is substantially more than the capacities of standard DVDs.

Flash is a type of non-optical memory (e.g., USB drives, SSDs) and not an optical device, making it irrelevant to the question's classification.