Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.
Q: Context : PetroChina Company Limited (simplified Chinese: ; traditional Chinese: ; Uyghur: ) is a Chinese oil and gas company and is the listed arm of state-owned China National Petroleum Corporation (CNPC), headquartered in Dongcheng District, Beijing.
Answer : China National Petroleum Corporation
A:
Which company is the parent company of PetroChina?