The power transmitted will be maximum when

Corona losses are minimum: This is not the correct answer. While minimizing corona losses is important for efficient power transmission, it doesn't directly determine the maximum power transmission. Maximum power transmission is influenced by factors such as sending and receiving end voltages.
Reactance is high: This is not the correct answer. High reactance can lead to increased voltage drop and reduced power transfer efficiency.
Sending end voltage is more: This is the correct answer. The power transmitted in a transmission line is given by the formula \( P = \frac{V_s^2}{Z} \), where \( P \) is power, \( V_s \) is sending end voltage, and \( Z \) is the total impedance of the line. Therefore, increasing the sending end voltage increases the power transmitted.
Receiving end voltage is more: This is not the correct answer. While receiving end voltage is important, the question specifically asks about maximizing power transmission, which is influenced by the sending end voltage.
Therefore, in the context of the question, the power transmitted will be maximum when the Sending end voltage is more (Option C).