What is the significance of the two different images?

"o captain! my captain! rise up and hear the bells;
rise up—for you the flag is flung—for you the bugle trills;
for you bouquets and ribbon'd wreaths—for you the shores a—crowding;
for you they call, the swaying mass, their eager faces turning;
here captain! dear father!
this arm beneath your head;
it is some dream that on the deck,
you've fallen cold and dead."

a. the speaker cannot believe that something wonderful has happened when everyone is so sad.
b. the speaker cannot believe that people will ever be able to feel happiness again after this event
c. the speaker cannot believe that people will ever be able to feel sadness again after this event
d. the speaker cannot believe that something terrible has happened when everyone is so happy.