IQ tests have proven to be good predictors of: A. social intelligence. B. practical problem-solving intelligence. C. school performance. D. all of the above.

Read the question carefully and understand the key terms. The question asks which of the given options are good predictors according to IQ tests. So, we must know the various types of intelligence and be able to identify what IQ tests measure.

Let's analyze each option to understand what they represent and if IQ tests are good predictors of them: A) Social intelligence: It encompasses emotional intelligence, empathy, interpersonal skills, and communication. IQ tests focus more on quantitative and logic-based skills rather than social abilities. B) Practical problem-solving intelligence: It is the ability to solve real-life challenges and adapt to the environment. IQ tests can somewhat measure practical problem-solving skills, but they mainly assess analytical and logical reasoning abilities, C) School performance: It's a measure of how well students perform in school through grades and standardized testing. IQ tests assess various cognitive skills, which are usually vital for school performance. D) All of the above: This option implies that IQ tests are good predictors of social intelligence, practical problem-solving intelligence, and school performance.

Based on our analysis of each option, we can confidently say that the best answer is: C) School performance - As mentioned earlier, IQ tests measure various cognitive skills that are vital for school performances, such as analytical and logical reasoning abilities. Additionally, multiple studies have reported a strong correlation between IQ scores and academic achievement. So, the correct answer to this question is C) School performance.