Answer ‘B’ is right https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag

I agree with FR99: B is the right option here. Explanation: The ETag HTTP response header is an identifier for a specific version of a resource. It allows caches to be more efficient and save bandwidth, since a web server does not need to resend a full response if the content has not changed. Additionally, etags help prevent simultaneous updates of a resource from overwriting each other Syntax: ETag: W/"<etag_value>" Directives:  W/ ( Optional) 'W/' (case-sensitive) indicates that a weak validator is used. Weak etags are easy to generate, but are far less useful for comparisons.  "<etag_value>" Entity tag uniquely representing the requested resource. They are a string of ASCII characters placed between double quotes, like "675af34563dc-tr34"

Agree with B. Some more reading: https://bigbinary.com/blog/rails-5-switches-from-strong-etags-to-weak-tags

Selected Answer: B B is correct. 'W/' (case-sensitive) indicates that a weak validator is used, which is optional. Weak etags are easy to generate, but are far less useful for comparisons. Strong validators are ideal for comparisons but can be very difficult to generate efficiently. Weak ETag values of two representations of the same resources might be semantically equivalent, but not byte-for-byte identical. This means weak etags prevent caching when byte range requests are used, but strong etags mean range requests can still be cached. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag

Selected Answer: B Correct answer: B 'W/' (case-sensitive) indicates that a weak validator is being used. Weak etags are easy to generate, but are far less useful for comparisons. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag

Selected Answer: B B works for me