Magnesium, reaction with alkyl halides form Grignard reagents

The reaction of metals with alkyl halide to form alkylmetal compounds is typical for lithium and magnesium. This so-called direct synthesis was applied to the preparation of both cyclopropyllithium" and derivatives and cyclopropylmagnesium halides under the standard preparative conditions of Grignard reagents without ring cleavage (equation 1). 

The answer is D. Alkyl magnesium halide or Grignard reagent can react with carbon dioxide to form carboxylic salts. The description of the reaction mentioned in the question also says that the reaction occured in acidic conditions. Under acidic conditions, the salt is converted to a carboxylic acid. So statement II is true. Furthermore, alkyl magnesium halide (Grignard reagent) acts as the nucleophile in the reaction. So statement III is tme. 

Studies on the reaction of magnesium with phenyl and alkyl halides at low temperature in the solid phase to form Grignard reagents point to Scheme 7. ... 

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