If \({\rm{\vec F}} = {\rm{x\;\vec i}} + {\rm{y\;\vec j}} + {\rm{z\;\vec k}}\) and s is the closed surface of x2 + y2 + z2 = a2. Then \(\mathop \int\!\!\!\int \nolimits_{\rm{s}}^{} {\rm{\vec F}} \cdot {\rm{\hat n\;ds}}\) is
1
\(\frac{4}{3}{\rm{\pi }}{{\rm{a}}^3}\)
2
πa3
3
4πa3
4
\(\frac{1}{3}{\rm{\pi }}{{\rm{a}}^3}\)