Which of the following lines contain alliteration?

meanwhile, his friend, through alley and street 1

wanders and watches with eager ears, 2

till in the silence around him he hears 3

the muster of men at the barrack door, 4

the sound of arms, and the tramp of feet, 5

and the measured tread of the grenadiers 6

marching down to their boats on the shore. 7

lines 1 and 2
lines 2, 3, 4
lines 6 and 7
line 4 only