Step-by-step explanation:
By Geometric mean property:
[tex] {y}^{2} = 4 \times 12 \\ \therefore \: {y}^{2} = 48 \\ \therefore \: {y} = \sqrt{48} \\ \therefore \: {y} = \sqrt{16 \times 3} \\ \huge \red{ \boxed {\therefore \: {y} = 4\sqrt{3} }}[/tex]
Thus, option A) 4√3 is the correct answer.
