The correct answer is: A. more expensive.
Hard disks are more expensive than diskettes because they have more storage capacity and are more durable. Hard disks can store up to several terabytes of data, while diskettes can only store up to 1.44 megabytes of data. Hard disks are also more durable than diskettes and are less likely to be damaged if they are dropped or mishandled.
Option B is incorrect because hard disks are not more portable than diskettes. Hard disks are larger and heavier than diskettes, and they require a power source to operate. Diskettes, on the other hand, are small and lightweight, and they do not require a power source to operate.
Option C is incorrect because hard disks are more rigid than diskettes. Hard disks are made of metal, while diskettes are made of plastic. This makes hard disks more resistant to damage from being dropped or mishandled.
Option D is incorrect because hard disks are more quickly accessed than diskettes. Hard disks have a faster access time than diskettes. This means that it takes less time for the computer to read data from a hard disk than it does to read data from a diskette.
Option E is incorrect because hard disks are not less expensive than diskettes. Hard disks are more expensive than diskettes because they have more storage capacity and are more durable.