Instruction: Extract the value of the target attribute from the given product information and output it along with the corresponding source.

Input:
Product title: Sony VAIO SVT21216CXB 21.5-Inch All-in-One Touchscreen Desktop (Discontinued by Manufacturer)
Product description: Surf the web, draw, play games, watch movies or work from any room. Meet the large, touchscreen PC that does what you want and goes where you need it.
Product feature: Intel Core i5-4200U 1.6 GHz, 8 GB DDR3L SDRAM, 1 TB 5400 rpm Hard Drive, 8 GB Solid-State Drive, 21.5-Inch Screen, Intel HD Graphics 4400, Windows 8
Product brand: Sony
Target attributes: Number of Cores
Answer: attribute: number of cores
value: None
source: None