The circumferential and longitudinal strains in a cylindrical boiler under internal steam pressure are $${\varepsilon _{\text{c}}}$$ and $${\varepsilon _l}$$ respectively. The change in volume of the boiler cylinder per unit volume will be

A. $${\varepsilon _{\text{c}}} + 2{\varepsilon _l}$$

B. $$2{\varepsilon _{\text{c}}} + {\varepsilon _l}$$

C. $${\varepsilon _{\text{c}}} + \varepsilon _l^2$$

D. $$\varepsilon _{\text{c}}^2 + {\varepsilon _l}$$

Answer: Option B