If the three medians of $\triangle ABC$ meet at $G$, then $AB^2 + BC^2 + AC^2 =$

• a$3(GA^2 + GB^2 + GC^2)$
• b$2(GA^2 + GB^2 + GC^2)$
• c$GA^2 + GB^2 + GC^2$
• d$4(GA^2 + GB^2 + GC^2)$