What idxmax returns on a filtered DataFrame

From a DataFrame of response times by hour for two servers, the code selects only server B's rows and finds the slowest hour. Predict the three lines of output without running the code.

Code

import pandas as pd

resp = pd.DataFrame({
    "server": ["A"] * 4 + ["B"] * 4,
    "hour": [9, 12, 15, 18] * 2,
    "ms": [120, 180, 150, 140, 90, 110, 210, 160],
})
b = resp[resp["server"] == "B"]
top = b["ms"].idxmax()
print(len(b))
print(top)
print(b.loc[top, "hour"])