The following ‘precautions’ were listed by a student in the experiment on study of ‘Dependence of current on potential difference’. (A) Use copper wires as thin as possible for making connections. (B) All the connections should be kept tight. (C) The positive and negative terminals of the voltmeter and the ammeter should be correctly connected. (D) The ‘zero error’ in the ammeter and the voltmeter should be noted and taken into consideration while recording the measurements. (E) The ‘key’ in the circuit, once plugged in, should not be taken out till all the observations have been completed. The ‘precautions’ that need to be corrected and revised are: (1) (A), (C) and (E) (2) (C) and (E) (3) (B) and (E) (4) (A) and (E)