1) b: acetic acid.
2) c: oxalic acid.
3) c: butanoic acid.
4) a: prop-2-enoic acid.
5) d: 2,3-dihydroxypropanoic acid.
6) c: 2-hydroxypropane-1,2,3-tricarboxylic acid.
7) c: 2-oxopropanoic acid.
8) a: benzoic acid.
9) b: cyclohex-5-ene-1,2-dicarboxylic acid.
10) a: 2-aminobenzoic acid.