The length of the straight portion of a bar beyond the end of the hook, should be at least

Answer: Option C

Reason: As per standard RCC detailing practice (IS 2502/IS 456), a hooked bar must have a straight extension beyond the hook to ensure adequate anchorage and prevent slip.

Minimum requirement: The straight portion beyond the end of the hook should be at least 4ϕ, where ϕ is the bar diameter.

Why 4ϕ? This length ensures the bearing and bond developed by the hook is effectively transferred into the concrete without premature pull-out or cracking at the bend.