Explanation: This scenario indicates an unexpected polarity in the DC system relative to ground. 1. **Understanding the reading:** In a standard DC system where the negative side is intentionally connected to ground (e.g., a ship's hull), a voltmeter between the negative line and ground should read 0 volts. If it reads the full line voltage (e.g., 12V), it means the negative line is at a potential difference of 12V relative to ground. 2. **Option B (Positive side grounded):** If the positive side of the line is unintentionally grounded, then ground effectively becomes the positive potential reference. In this situation, the negative side of the line would be at the full line voltage *below* ground potential (e.g., if +12V is grounded, the negative line is at 0V relative to the generator, but -12V relative to ground). A voltmeter connected between this negative line (-12V) and ground (0V) would indeed show a potential difference equal to the full line voltage (12V). Thus, the reading indicates the positive side is grounded. 3. **Option C (Generator terminals reversed):** If the positive side is grounded instead of the negative, the entire system's polarity is effectively reversed with respect to the ship's ground. To correct this and re-establish the negative side as the grounded terminal, the output polarity of the DC generator would need to be reversed. Since the voltmeter reading directly indicates that the positive side is grounded (B), and reversing the generator terminals (C) is the corrective action to properly ground the negative side, both statements are correct in describing the situation and its remedy.