Match List-I with List-II:

	List-I		List-II
A.	K	I.	Thermonuclear reactions
B.	KCl	II.	Fertilizer
C.	KOH	III.	Sodium potassium pump
D.	Li	IV.	Absorbent of CO$$_2$$

Let us match each item from List-I with List-II:

A. K (Potassium): Potassium ions play a crucial role in the sodium-potassium pump in biological systems, which maintains the electrochemical gradient across cell membranes. → III. Sodium potassium pump

B. KCl (Potassium chloride): KCl is widely used as a potash fertilizer in agriculture. → II. Fertilizer

C. KOH (Potassium hydroxide): KOH is used as an absorbent of CO$$_2$$ in various applications. → IV. Absorbent of CO$$_2$$

D. Li (Lithium): Lithium is used in thermonuclear reactions (hydrogen bombs), where lithium deuteride serves as the fusion fuel. → I. Thermonuclear reactions

The correct matching is: A(III), B(II), C(IV), D(I).