Could someone answer this question so I understand it. Thanks

Question

In general, the most elegant way to add one carbon with an OH on it to a primary alkyl halide is to:

a) convert the alkyl halide to a Grignard and add formaldehyde followed by H3O.

b)convert the alkyl halide to a lithium dialkyl cuprate and add formaldehyde followed by H3O

c) convert the alkyl halide to an alcohol, oxidize the alcohol to an aldehyde and treat with methyl Grignard followed by H3O

d) convert the alkyl halide to a grignard and add oxirane followed by H3O

e) convert the alkyl halide to a grignard and add ethyl formate