多选题

What is the output of the last "t()" ...

Question

What is the output of the last "t()" in Python code?

    def t(a = []):
        a.append(1)
        print(a)

    t()
    t()
    t()
    t()

A. []

B. [1]

C. [1, 1, 1, 1]

D. [1, [1, 1], [1, 1, 1], [1, 1, 1, 1]]