Which one of the following is not used in organic farming?

If $A$ is a square matrix such that $A(\operatorname{adj} A) = \begin{bmatrix} 4 & 0 & 0 \\ 0 & 4 & 0 \\ 0 & 0 & 4 \end{bmatrix}$,then $\operatorname{det}(\operatorname{adj} A)$ is equal to

$CH_3 - C \equiv CH$ $\xrightarrow{Na} X$ $\xrightarrow{CH_3 - Cl} Y$,
$Y$ is

The sum of two numbers is $20$. If the product of the square of one number and the cube of the other is maximum,then the numbers are:

$\sec ^2(\tan ^{-1} 2) + \operatorname{cosec}^2(\cot ^{-1} 3)$ is equal to

Cuscuta is an example of