A compound with molecular formula C₄H₆O₄ produces a broad signal between 2500 and 3600 cm-1 in its IR spectrum and produces two signals in its ¹H NMR spectrum (a singlet at 12.1 ppm with a relative integration of 1 and a singlet at 2.4 ppm with a relative integration of 2). Deduce the structure of the compound.