Final answer:
Parity bits are used for error correction for every compressed block. They help to ensure the accuracy of data during transmission or storage by checking the sum of '1' bits to detect inconsistencies, unlike Huffman coding and Run-Length Encoding, which are compression techniques, or checksums, which are used for integrity checks but not specifically block error correction.
Step-by-step explanation:
The technique used for error correction for every compressed block is b) Parity bits. Parity bits are a form of error detection that is often used in computer memory and network communications to ensure the accuracy of data. When data is transmitted or stored, a parity bit is added to the end of the data block. It checks whether the number of set bits, meaning the bits that are '1', is odd or even. Parity can either be even or odd; in even parity, the parity bit is set in such a way that the total number of '1' bits is even, while for odd parity, it's set so the number of '1' bits is odd. This technique helps in detecting errors that may occur during data transmission or storage. If the parity doesn't match at the receiving end, an error is indicated, and the specific block can be requested again or corrected using further error correction techniques.
Huffman coding (a) and Run-Length Encoding (d) are actually methods used for data compression, not error correction. Checksums (c), similar to parity bits, are used to check the integrity of data during transmission or storage, but they are not used for error correction of every compressed block specifically.