The function to get the index of maximum value in a column of DataFrame is …………… .

1. max()
2. index()
3. idxmax()
4. maxidx()

To get top 5 rows of a DataFrame, you may use …………… function.

1. head()
2. head(5)
3. top()
4. top(5)

Function …………… can be used to drop missing values.

1. fillna()
2. isnull()
3. dropna()
4. delna()

Which of the following methods of combining two DataFrames is a patching method ?

1. concat()
2. merge()
3. join()
4. none of these