A

Step 1: Analyze the relationship between current in the circuit and the parameters that affect it. The current in a circuit depends on the total resistance present, which includes the load and any internal resistance. Hence, the matching option is [A].
Step 2: Consider the maximum power that can be developed by a given cell. According to maximum power transfer theorem, maximum power transfer occurs when the load resistance is equal to the internal resistance of the source. Therefore, this corresponds to option [B].
Step 3: Evaluate the terminal potential difference of a cell in the circuit. The terminal potential difference is affected by the internal resistance of the cell and is given by the equation: $$ V = E - Ir $$ where $E$ is the EMF, $I$ is the current, and $r$ is the internal resistance. Hence, this matches with option [C].
Step 4: Assess the potential drop across the load resistance. The potential drop across the load resistance in a circuit is influenced by the EMF of the cell, as given by Ohm’s law. Accordingly, this matches with option [D].
Final Matching:
(i) -> [A]
(ii) -> [B]
(iii) -> [C]
(iv) -> [D].
Therefore, the correct answer is A.