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since words have multiple meanings, the context of a word often clues its meaning better than the dictionary's definition. in the following lines from anne bradstreet's poem, "to her father witih some verses," what is the best definition for principal?

"most truly honored, and as truly dear,
if worth in me or ought i do appear,
who can of right better demand the same
than may your worthy self from whom it came?
the principal might yield a greater sum,
yet handled ill, amounts but to this crumb;
my stock's so small i know not how to pay,
my bond remains in force unto this day."

a) the head of a school
b) a primary reason
c) catching
d) rare