A school must select four of the seven students A. B, C, Gu, Wu, Ji, and G to form a debate team to participate in the city's debate competition. According to the usual training situation, the selection must meet the following conditions: To participate, C must also participate; unless B participates, Geng does not participate; at least one of A and B participates, but not both; at least one of Wu Heji, but not both. Based on the above statement, which of the following students will definitely participate in the debate contest? ['B or G, or both.', 'Wu or Geng, or both.', 'C or D, or both.', 'C or E, or both.']