Which of the following are correct methods for the preparation of propanoic acid ?
A. `H_(3)C-CH=CH_(2)overset(HBr)rarroverset(Mg)underset(Ether)rarroverset(CO_(2))underset(H_(3)^(oplus)O)rarr`
B. `H_(3)C-C-=CHoverset(BH_(3).THF)underset(H_(2)O_(2),.^(Θ)OH)rarroverset(KMnO_(4))rarr`
C. `H_(2)C=CH_(2)overset(HBr)rarroverset(Mg)underset(Ether)rarroverset(CO_(2))underset(H_(3)^(oplus)O)rarr`
D. `H_(3)C-CH=underset(CH_(3))underset(|)C-CH_(3)overset(O_(3))underset(Ag_(2)O)rarr`
