Question: Àtòpọ̀ àwọn lẹ́tà wo ni ó lè jẹ́ lílò gẹ́gẹ́ bí àpẹẹrẹ kẹ́mìkà fún ohun-aláìṣeépin kan? 
Options:
BR
ChI
Dy
FeO
Answer: C