What is Pinyin?
Pinyin is the official system in mainland China, Singapore and Taiwan for transcribing Standard Chinese with the Latin alphabet. It is often used to teach Standard Chinese, which is normally written using Chinese characters. Pinyin without tone marks is often used in foreign publications to spell Chinese names familiar to non-Chinese and may be used as an input method to enter Chinese characters into computers. The word pīnyīn (Chinese: 拼音) literally means "spelled-out sounds".
The "wrong" answers are related to three similar-sounding words:
(1) Pinin is the name for the protein mentioned.
(2) Piyi is the name of a crater on Mars.
(3) Pingyin is the name of a county under the administration of Jinan, the capital of Shandong province, China.