Instruction: Using the product's title, description, features, price, and brand, identify and retrieve the values associated with a specified set of target attributes. Output the extracted values along with their respective sources (e.g., title or feature) indicating where each value was found.

Input:
Product title: LaBella 900B La Bella Guitar String Set
Product description: Classical Guitar Strings, Polished Gold Alloy Winding, .028-.043
Product feature: La Bella Model#900BLAB
Product price: $0.91
Product brand: La Bella
Target attributes: Acoustic / Electric
Answer: attribute: acoustic / electric
value: None
source: None