\(\rm{25℃}\)时,用\(\rm{NaOH}\)溶液滴定\(\rm{H_{2}C_{2}O_{4}}\)溶液,溶液中\(\rm{-\lg \dfrac {c(H^{+})}{c(H_{2}C_{2}O_{4})}}\)和\(\rm{-\lg c(HC_{2}O_{4}^{-})}\)或\(\rm{-\lg \dfrac {c(H^{+})}{c(HC_{2}O_{4})}}\)和\(\rm{-\lg c(C_{2}O_{4}^{2-})}\)关系如图所示,下列说法正确的是\(\rm{(}\) \(\rm{)}\)