Keep calm and carry on looks at official and instructive language.
Signs and notices, formal letters etc in English have a particular style to them which may sometimes seem at odds with 'normal everyday' usage. How good are you at identifying and making sense of such expressions? 'Keep calm and carry on'!
Answer 1 remains slightly vague; Answer 2 misinterprets the word 'unleaded' ('un-LEDD-id', as in car fuel; not 'un-LEED-ed'): Answer 3 is too wordy.
'Leash' is a slightly old-fashioned equivalent word for 'lead' in this context.
Meanwhle you may have noticed that nothing is said about 'assistance dogs' (guide dogs for the blind, and equivalent trained dogs for those who are deaf or have other impairments).