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: Unlocked KTD® 2 Sim Mtk6572w Cortex A7 Dual Core, 1.3ghz Android 4.2 Smart Phone 4.0 Inch Compatible with GSM Carriers T-mobile Simple Mobile At&t Straight Talk Net 10 Wifi Multi Touch Screen 4" Cell Phone
Product description: phone's only, no sim card and sd card provided. 2G only, no 3G/4G data connection. This device is also build in WiFi, bluetooth and quad-band GSM . It work for ATT /T-mobile GSM prepaid sim. but not for sprint/verizon or other network.
Product feature: Android, 4" multi touch screen, GSM unlocked for ATT Tmobile straight talk, no 3G/4G data connection,Could not work in verizon, WIFI,Bluetooth,Dual core.
Product brand: KTD
Target attributes: Screen Size
Answer: attribute: screen size
value: 4"
source: product feature
attribute: screen size
value: 4.0 inch
source: product title
attribute: screen size
value: 4"
source: product title