Instruction: Given the title, description, feature, price, and brand of a product and a set of target attributes, extract the value of each target attribute from the product information. Output the extracted value and the corresponding source (e.g., title or feature) denoting where the value is extracted.

Input:
Product title: ASUS CM1735-US003O Desktop (Discontinued by Manufacturer)
Product description: ASUS 1735 is your everyday multimedia center that delivers great HD experience and performance so you can enjoy both work and play. Enhance your experience with ASUS exclusive feature and technology. Feel confidence on ASUS Desktop as it rank as leading reliability brand by PCWorld 2011 User Survey.
Product feature: AMD A4-3420 Processor 2.8 GHz, 4GB DDR3, 1 TB 7200 rpm Hard Drive
Product brand: Asus
Target attributes: Operating System
Answer: attribute: operating system
value: None
source: None