In harper lee’s to kill a mockingbird, the image of the mockingbird carries great symbolic weight. based on the following excerpt, what could the mockingbird symbolize?

mockingbirds don't do one thing but make music for us to enjoy. they don't eat up people's gardens, don't nest in corncribs, they don't do one thing but sing their hearts out for us. that's why it's a sin to kill a mockingbird.

a.
the mockingbird symbolizes the beauty of music because it gives immense pleasure to people through its melodious singing.
b.
the mockingbird symbolizes the softer side of nature, because unlike most wild creatures, it doesn’t harm human habitat.
c.
the mockingbird symbolizes life that should be preserved for the nonmaterial value it provides people through its singing.
d.
the mockingbird symbolizes the aesthetic beauty of nature because it lifts the moods of people by singing its heart out.