How does enjambment effect the meaning and emotion of a poem?

It keeps the poem moving forward and is often used to soften a rhyme. When a line ends with the rhyme it can sound too 'rhymy'...enjambment helps soften this by keeping the flow so it moves past the rhymed word and the rhyme almost appears to be an internal one. Listen: 

Winners must choose 
The deaf cannot hear 
Drunkards love booze 
Muds far from clear 

now try, 

sometimes we choose 
to listen but not hear 
the truth found in booze 
when our thinking's less clear 

Although not a great poetic stanza, the lines are enjambed and flow from line to line keeps the rhymes from sounding so rhymy. 

Enjambment can also assist the poet when the rhymed word "is" in the middle of a sentence and the previous sentence's thought ends before the end of a line...for example: 

Freighted with hope, 
Crimsoned with joy, 
We scatter the leaves of our opening rose; 
Their widening scope, 
Their distant employ, 
We never shall know. And the stream as it flows 
Sweeps them away 

The sencond to last line posted shows how the previous line's sentence ended mid-line. The new sentence picks up and the word "flows", which makes the line rhyme with "rose" three lines earlier, goes almost unnoticed. This is an outstanding example of good enjambment. 

The answer to that question is b