According to the passage, how to understand “wear their hearts on their sleeves like Americans” in paragraph 1?

A、Americansliketoweartheirheartsontheirsleeves.
B、Americansliketoshowtheirheartswiththeirsleeves.
C、Americansaredifficulttoshowtheiremotions.
D、Americansareeasytoshowtheiremotions.