This is an excerpt from "when we two parted" by lord byron.

they name thee before me,

a knell to mine ear;

a shudder comes o'er me—

why wert thou so dear?

they know not i knew thee,

who knew thee too well: --

long, long shall i rue thee,

too deeply to tell.

in secret we met—

in silence i grieve,

that thy heart could forget,

thy spirit deceive.

if i should meet thee

after long years,

how should i greet

with silence and tears.

what is its overall tone?

a. somber

b. distressful

c. bittersweet

d. joyful