Final answer:
A polite euphemism for being short is "vertically challenged," which is a humorous and respectful way to refer to someone's height.
Step-by-step explanation:
A polite euphemism for being short is "vertically challenged." This term is a humorous way to describe someone who is not very tall without directly pointing out their lack of height. Euphemisms like this are often used to address potentially sensitive subjects with a touch of levity or respect.
While "altitude challenged" in the options provided could be seen as a whimsical variant, "vertically challenged" is more commonly understood and used in English-speaking cultures. It's important to keep the tone friendly and not to use these descriptions in a way that might offend the person being referred to.