Arrange the following optical storage devices in decreasing order of their storage capacity.

A. DVD

B.CD-ROM

C. Blue-Ray

Choose the correct answer from the options given below:

The correct answer is C, A, B.

To arrange the given optical storage devices in decreasing order of their storage capacity, let's look at the standard storage capacities of each format:

1. Blue-Ray (C): Blu-ray discs have the highest storage capacity among the three. A standard single-layer Blu-ray disc can hold about 25 GB of data, and dual-layer discs can hold up to 50 GB. This large capacity is achieved by using a blue-violet laser with a shorter wavelength, allowing data pits to be packed much more tightly.

2. DVD (A): Digital Versatile Discs have a moderate storage capacity. A standard single-layer, single-sided DVD holds approximately 4.7 GB of data, while dual-layer versions can store up to 8.5 GB.

3. CD-ROM (B): Compact Disc Read-Only Memory has the lowest storage capacity of the group. A standard CD-ROM typically holds about 700 MB (megabytes) of data, which is approximately 0.7 GB.

Comparing these values:
Blu-ray (25 GB to 50 GB) > DVD (4.7 GB to 8.5 GB) > CD-ROM (0.7 GB)

Therefore, the decreasing order of storage capacity is C, A, B.