The Secure Hash Algorithm (SHA-1) of the Secure Hash Standard (NIST
FIPS PUB 180) processes data in block lengths of:

A.
128 bits.

B.
256 bits.

C.
512 bits.

D.
1024 bits.

Explanation:
The correct answer is 512 bits. If a block length is fewer than 512 bits,
padding bits are added to make the block length equal to 512 bits.
The other answers are distracters.