The use of the phrase "wear one's heart upon one's sleeve" can be traced to these lines from Shakespeare:
Heaven is my judge, not I for love and duty,
But seeming so, for my peculiar end:
For when my outward action doth demonstrate
The native act and figure of my heart
In compliment extern, 'tis not long after
But I will wear my heart upon my sleeve
For daws to peck at: I am not what I am.
(from Othello by William Shakespeare)

Based on the context in the source, what is the likely meaning of the idiom "to wear one's heart upon one's sleeve"?
A) to feel deeply sorrowful
B) to be cold and unemotional
C) to openly show inner feelings
D) to be outwardly attractive