If $0.5$ mole of $BaCl_2$ is mixed with 0.2 mole of $Na_3PO_4$,the maximum number of moles of $Ba_3(PO_4)_2$ that can be formed is :

Question

$(a)\;0.7\qquad(b)\;0.5\qquad(c)0.30\qquad(d)\;0.1$