Commands tar & dd
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dd allows block sizes to be defined, tar does not allow
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tar allow block sizes to be defined while dd does not allow
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both tar & dd allow block sizes to be modified
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both tar & dd do not allow block sizes to be modified
Both tar and dd support configurable block sizes: tar uses -b or --blocking-factor (in 512-byte blocks), while dd uses bs= for direct byte-level I/O block specification.
Both the 'tar' and 'dd' commands support explicitly setting block sizes: tar accepts a '-b' (blocking factor) option, and dd accepts 'bs=' (or ibs=/obs=) to define the block size used for reads/writes. Since both utilities allow this to be configured, the correct statement is that both allow block sizes to be modified — the other options, which claim only one of the two supports it or neither does, are factually wrong about at least one command's capabilities.