Enzyme X breaks down protein in the stomach. Four test-tubes were arranged, and each one contained equal amounts of protein and enzyme X. The test-tubes were maintained at different pH values and temperatures. In which test-tube will protein digestion be fastest?
- ApH 2, $20^{\circ}\text{C}$
- BpH 2, $35^{\circ}\text{C}$
- CpH 7, $20^{\circ}\text{C}$
- DpH 7, $35^{\circ}\text{C}$