What is the most expensive CSU school?

Could you please clarify which CSU school you're referring to, as there are multiple California State Universities across the state? Assuming you're asking about the California State University system, I'd be curious to know which campus within the system is considered the most expensive in terms of tuition and fees. Is there a particular reason why you're interested in this information, such as planning to attend a CSU school or comparing costs between institutions? I'd be happy to provide more context and details once we've clarified the specific CSU school you're inquiring about.