The product of additive inverse and multiplicative inverse of $\dfrac{-1}{4}$ is

1. 1

2. -1

3. 0

4. $\dfrac{-1}{16}$

To find the additive inverse, change the sign of the number, and to find the multiplicative inverse, interchange its numerator and denominator.

Additive inverse of $\dfrac{-1}{4} = \dfrac{1}{4}$

Multiplicative inverse of $\dfrac{-1}{4} = \dfrac{4}{-1} = -4$

Multiplying both the inverses,

$\Rightarrow \dfrac{1}{4} \times (-4) \\[1em] \Rightarrow \dfrac{1 \times (-4)}{4} \\[1em] \Rightarrow \dfrac{-4}{4} = -1$

Hence, Option 2 is the correct option.