Which of the following is the most important theoretical difference regarding the structure of intelligence between Gardner's Theory of Multiple Intelligences and Spearman's Two-Factor Theory?

According to Howard Gardner's Theory of Multiple Intelligences, there is no single general center of intelligence, but rather multiple independent types of intelligences (such as linguistic, logical-mathematical, spatial, musical, etc.). In contrast, Charles Spearman's Two-Factor Theory talks about the 'G' (General factor) and 'S' (Specific factor) factors, where the 'G' factor is generally present in all types of intellectual activities. For a more detailed study, you can see the Wikipedia reference.