Question

b. which of the following describes the set of moving poems?
a. it is not well defined. there is no clear meaning of \moving.\
b. it is not well defined. there is no clear meaning of \poems.\
c. it is well defined. for a given thing, it is possible to tell whether it is a poem
d. it is well defined. for a given poem, it is possible to tell whether it is moving
e. it is not well defined. although there is a clear meaning of \poems,\ it is not possible to tell whether a poem is moving
f. it is well defined. it is possible to list all of the moving poems in the world

Explanation:

A well - defined set has a clear rule to determine membership. For "moving poems", the term "moving" is subjective (no clear meaning), so we can't clearly tell if a poem is in the set. Option A says it's not well - defined due to unclear "moving", which matches.

Answer:

A. It is not well defined. There is no clear meaning of "moving."