BRAINLIESTTT ASAP!!!! PLEASE ANSWERRR


What does William Wordsworth mean by "They" in the following bolded line?
Continuous as the stars that shine
And twinkle on the milky way,
They stretched in never-ending line
Along the margin of a bay:
Ten thousand saw I at a glance,
Tossing their heads in a sprightly dance.

people
daffodils
clouds
stars