In "the charge of the light brigade," how does the poet use alliteration in lines like "stormed with shot and shell" and "the saber stroke / shattered and sundered"?

a.
to add sound effects of battle to the poem's description of the action

b.
to prove that the soldiers of the light brigade were outnumbered

c.
to remind readers about which weapons were used in the battle

d.
to question the officer's decision to make the charge

i think a.. but im not sure..