次のスクリプトを実行した結果として正しいものはどれか。
import pandas as pd
df = pd.DataFrame([[40, "a", True],[20, "b", False],[30, "c", False]])
df.index = ["01", "02", "03"]
df.columns = ["A", "B", "C"]
def judge(arg):
if arg < 50:
return "low"
elif arg < 70:
return "middle"
else:
return "high"
df.loc[:, "C"] = df.iloc[:, 0] * 2
df.loc[:, "B"] = df.iloc[:, 2].apply(judge)
_ = df["C"] > 50
df = df[_]
print(df.iloc[0 , 0], df.iloc[1 ,1])