def mostFrequent(df):
    """Show the most frequent hour,day, or month for starting to rent a bike
        arguments:
        df -- the DataFrame 
    """
    # extract hour from the Start Time column to create an hour column
    df['hour'] = df['Start Time'].dt.hour
    # find the most common hour (from 0 to 23)
    popHour = df['hour'].mode()[0]
    # extract day from the Start Time column to create an day column
    df['day'] = df['Start Time'].dt.day
    # find the most common day (from 1 to 31)
    popDay = df['day'].mode()[0]
    # extract month from the Start Time column to create an month column
    df['month'] = df['Start Time'].dt.month
    # find the most common month (from 1 to 12)
    popMonth = df['month'].mode()[0]
    return (popHour, popDay, popMonth)