The volume of the given solid is :

1. $\dfrac{4}{3}πr^3$

2. $\dfrac{4}{3}πr^2$

3. 2πr³

4. 4πr³

From figure,

Height of cone (h) = r

Height of cylinder (H) = r

Radius of hemispherical portion = Radius of cylindrical portion = Radius of conical portion = r.

From figure,

Volume of body = Volume of conical portion + Volume of cylindrical portion + Volume of hemispherical portion

$= \dfrac{1}{3}πr^2h + πr^2H + \dfrac{2}{3}πr^3 \\[1em] = \dfrac{1}{3}πr^2.r + πr^2.r + \dfrac{2}{3}πr^3 \\[1em] = \dfrac{1}{3}πr^3 + πr^3 + \dfrac{2}{3}πr^3 \\[1em] = \dfrac{πr^3 + 3πr^3 + 2πr^3}{3} \\[1em] = \dfrac{6πr^3}{3}\\[1em] = 2πr^3.$

Hence, Option 3 is the correct option.