The product of two rational numbers is -1, if one of them is $\dfrac{2}{5}$, then the other is :

1. $-\dfrac{2}{5}$

2. $\dfrac{5}{2}$

3. $-\dfrac{5}{2}$

4. none of these

Statement 1: For a rational number $\dfrac{7}{9}, \dfrac{7}{9} - 0 = \dfrac{7}{9} \text{ and } 0 - \dfrac{7}{9} = - \dfrac{7}{9}$. Hence, Subtraction has only right identity.

Statement 2: Subtraction has no identity.

Which of the following options is correct?

1. Both the statement are true.

2. Both the statement are false.

3. Statement 1 is true, and statement 2 is false.

4. Statement 1 is false, and statement 2 is true.

Assertion (A) : Multiplicative inverse of $-\dfrac{7}{5} \text{ is } -\dfrac{5}{7}$.

Reason (R) : For every non-zero rational number 'a', there is a rational number $\dfrac{1}{a}$ such that $a \times \dfrac{1}{a} = 1$.

1. Both A and R are correct, and R is the correct explanation for A.

2. Both A and R are correct, and R is not the correct explanation for A.

3. A is true, but R is false.

4. A is false, but R is true.

Assertion (A) : $\dfrac{1}{2} + 2 = \dfrac{5}{2}$, which is a rational number.

Reason (R) : If $\dfrac{p}{q} \text{ and } \dfrac{r}{s}$ are any two rational numbers then $\dfrac{p}{q} + \dfrac{r}{s} = \dfrac{r}{s} + \dfrac{p}{q}$.

1. Both A and R are correct, and R is the correct explanation for A.

2. Both A and R are correct, and R is not the correct explanation for A.

3. A is true, but R is false.

4. A is false, but R is true.