A Scientist Found an Unweathered Igneous Rock That Contained

A scientist found an unweathered igneous rock that contained .025 g of potassium-40 and 075 g of argon-40. The half-life of potassium-40 is 1.3 billion years. The rock would be estimated to be

A) 2.6 billion years old.
B) 0.050 billion years old.
C) 1.3 billion years old.
D) 0.001875 billion years old.
E) 1.69 billion years old.