Which one of these excerpts from mark twain's life on the mississippi best shows that the story is told in first person?
a. ten minutes later the steamer is under way again, with no flag on the jack-staff and no black smoke issuing from the chimneys.
b. boy after boy managed to get on the river. the minister's son became an engineer.
c. when i was a boy, there was but one permanent ambition among my comrades in our village on the west bank of the mississippi river.
d. the "point" above the town, and the "point" below, bounding the river-glimpse and turning it into a sort of sea?