Technically the answer would be a
True
In Coleridge's Biographia Literaria, he says that it is legitimate to call any composition composed using rhyme and meter a poem. In the text he says, "If a man chooses to call every composition a poem, which is rhyme, or measure, or both, I must leave his opinion uncontroverted." He goes on to repeat this when he says, "the composition will be a poem, merely because it is distinguished from composition in prose by metre, or by rhyme, or by both conjointly." In both of these he asserts that a poem is a composition with rhyme and meter.
So, a possessive noun is usually used to indicate who or what has something, like "The Dogs' ball."
To change this form of children,plural, to a possessive noun, you will want to add an apostrophe, and then an s. It changes to this:
Children's
