Carbonation of Grignard reagent with a carbonyl group present in it
You should look at two things:

1)  Will the reaction stay on course?  If you add water to the Grignard reagent first, without the carbon dioxide initially, what do you get?  Is it something that will get you your carboxylic acid when you add the carbon dioxide?

2)  Can you make the Grignard reagent to begin with?  Here again you are asking the reaction to stay on course; if the Grignard function can react with another functional group in the molecule, it will do so either within the molecule or as an intermolecular reaction between two of the molecules. 
Then you no longer have your Grignard reagent.

Only one of the given possibilities works against both of these questions, so there is your answer.