How does the use of alliteration in these lines influence the reader's emotions? and maggie discovered a shell that sang so sweetly she couldn't remember her troubles, and

An alliteration points to the first letters being the same (or same sounding) for a series of words. 

In this case "s" is the alliteration. In the English language the sound of "s" is used to hush or clam someone. "S" or "Huh" 

Well what are the options