下面Python代码的输出结果正确的是？（ ）
import numpy as np
student = np.dtype([('name','S20'), ('age', 'i2'),('height', 'f4')])
a = np.array([('Alice', 20, 55),('Jone', 21, 48)], dtype = student)
print(a)
[(b'Alice', 20., 55.) (b'Jone', 21., 48.)]
[(b'Alice', 20., 55) (b'Jone', 21., 48)]
[(b'Alice', 20, 55.) (b'Jone', 21, 48.)]
{(b'Alice', 20, 55.), (b'Jone', 21, 48.)}