Which line of Thomas Gray's Elegy Written in a Country Churchyard ponders the existence of unrecognized human potential?

(1 point)
"For them no more the blazing hearth shall burn..."
"One morn I missed him on the custom'd hill..."
"Full many a flow'r is born to blush unseen..."
"The plowman homeward plods his weary way..."

"Full many a flow'r is born to blush unseen..."