Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: Arista 18-2970 6 foot 3.5mm M/M Stereo Cable
Product description: 6' stereo cable w/ 3.5mm stereo plugs / For connecting a portable CD player to a home stereo system
Product feature: 6-foot stereo cable with male miniplug (3.5mm) connectors
Product price: $4.49
Product brand: Arista
Target attributes: Audio Channels
Answer: attribute: audio channels
value: stereo
source: product description
attribute: audio channels
value: stereo
source: product feature
attribute: audio channels
value: stereo
source: product title