Answer: B, Lingxingyu
Answer analysis:
When discussing the control systems mainly used in Sanxinwei's current full-color display products, we need to analyze based on industry common sense, market popularity and the professionalism of each control system.
A, Weiao Shixun: This option is not a well-known control system brand in the market, especially in the field related to full-color display control systems. Therefore, it is unlikely to be the main control system for Sanxinwei's full-color display products.
B, Lingxingyu: Lingxingyu is a well-known domestic LED display control system brand, widely used in various LED display projects, including full-color displays. It enjoys a high reputation in the market for its stability and efficiency, so it is one of the control systems that Sanxinwei may choose.
C, Depuda: Although Depuda may have its applications in some fields, it is not a mainstream brand in the market of full-color display control systems. Therefore, this option is also unlikely to be the main choice of Sanxinwei.
D, Zhongqing: Zhongqing is not a brand with LED display control systems as its main product. Its business field may be wider, but it is not focused on this. Therefore, this option is also unlikely to be the main control system for Sanxinwei's full-color display products.
In summary, considering the market popularity, brand awareness and professionalism, the control system currently used by Sanxinwei's full-color display products is most likely Lingxingyu.
Therefore, the correct answer is B, Lingxingyu.