下面可以正确输出 They're planning a party for their friend's birthday. 的Python语句是？ （ ）
A.
print('They\'re planning a party for their friend\'s birthday.")
B.
print("They\'re planning a party for their friend\'s birthday.')
C.
print('They're planning a party for their friend's birthday.')
D.
print('They\'re planning a party for their friend\'s birthday.')
