If the half-life of K-40 is 1.3 billion years and if a sample rock found on an island is estimated to be 1 billion years old, what percentage of the original parent K-40 would be present in the rock? Round your numerical values to the hundredths decimal place.

Answer Choices

(A) 76.92%
(B) 1.3%
(C) 58.67%
(D) 99.99%

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