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: K620 - NVIDIA K620 PNY Quadro K620 2GB 128-bit DDR3 Graphics Card NVIDIA Quadro K620-VCQK620-PB
Product description: 100% Genuine- Computer/Laptop Replacement or Internal parts NVIDIA K620 PNY Quadro K620 2GB 128-bit DDR3 Graphics Card NVIDIA Quadro K620-VCQK620-PB Brand: NVIDIA Part Number: K620 Screen Resolution:3840 x 2160 pixels Max Screen Resolution:3840 x 2160 RAM:2 GB Graphics Coprocessor:NVIDIA Chipset NVIDIA Graphics Card Ram Size:2 Name:PNY Item model number:VCQK620-PB Item Weight:1.1 pounds Product Dimensions:11 x 6.4 x 2.7 inches Item Dimensions L x W x H:11 x 6.4 x 2.7 inches Processor Count:1 Computer Memory Type:DDR3 SDRAM Note: Please ensure that your original part number matches this exactly, or check with the manufactuer for compatiblity. Customers are responsible for compatiblity. Picture may not match actual product. Please contact Seller for more detailed pictures in the event of an unclear image. This part is guaranteed to be fully functional, original and authentic. Many of these parts and models are old; please contact the individual sellers if more details are needed.
Product feature: Please ensure that your original part number matches this exactly, or check with the manufactuer for compatiblity. Customers are responsible for compatiblity., This part is guaranteed to be fully functional, original and authentic., K620
Product price: $3.91
Product brand: NVIDIA
Target attributes: Output Resolution
Answer: attribute: output resolution
value: 3840 x 2160
source: product description