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: Hohner 145RDBX-C Red Dragon Harmonica, Key of C
Product description: Celebrating the soul and spirit of the street artist, HOHNERs newest harmonicas look strikingly different, featuring brightly colored combs and patterns that were inspired by street artists and skateboard decks. Available in the Key of C, G and A
Product feature: 1 Diatonic Harmonica in the Key of C, Red comb, Brass reed plates, Stainless Steel Covers
Product price: $0.91
Product brand: Hohner Accordions
Target attributes: Key
Answer: attribute: key
value: key of c
source: product description
attribute: key
value: key of c
source: product title
attribute: key
value: key of c
source: product feature