Final answer:
Shandong option(c) province shares the closest economic ties with South Korea, largely due to its geographical proximity which supports active trade and economic interactions.
Step-by-step explanation:
The province in China that shares the closest economic ties with South Korea is Shandong. This is due to its geographical proximity to the Korean Peninsula, which facilitates trade and economic interactions.
The Liaoning province, part of the region formerly known as Manchuria and noted for its industrial centers such as Harbin and Shenyang, also maintains strong ties with South Korea, but Shandong's economic relationship with South Korea is particularly close due to the active and versatile exchanges in goods and services between them.