Read the riddle and answer the question. Pay special attention to the bolded phrases.
OFTEN I must war against the wave
and fight against the wind;
I contend against them combined, when,
buried by the billows, I go to seek the earth;
my native land is strange to me.
If I grow motionless I am mighty in the conflict;
if I succeed not in that they are stronger than I,
and straightway with rending they put me to rout;
they wish to carry off what I must keep safe.
I foil them in that if my tail endures and
if the stones are able to hold fast against me in my strength.
Ask, what is my name?
The speaker in the riddle is a(n)_____.
anchor
sail
ship's hull
oar