Assertion (A). The output of addition of two series will be NaN, if one of the elements or both the elements have no value(s).

Reason (R). While performing mathematical operations on a series, by default all missing values are filled in with 0.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Name the function to iterate over a DataFrame horizontally.

Write equivalent expressions for the given functions :

(i) A.add(B)

(ii) B.add(A)

(iii) A.sub(B)

(iv) B.sub(A)

(v) A.rsub(B)

(vi) B.mul(A)

(vii) A.rdiv(B)

(viii) B.div(A)

(ix) B.rdiv(A)

(x) A.div(B)

Is the result of sub() and rsub() the same? Why/why not ?