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: 2015 Canada Grey Wolf - 3/4 oz pure Silver Coin - $2 Brilliant Uncirculated
Product feature: Grey Wolf Coin, Minted by the famous Royal Canadian mint, 3/4 troy ounces, 99.99% fine pure Silver
Target attributes: Type
Answer: attribute: type
value: silver
source: product feature
attribute: type
value: silver
source: product title
attribute: type
value: coin
source: product feature