A sample of silicon rejected for use in an electronic circuit has an impurity of boron at a 22) level of 3 parts per trillion. What is the fraction of boron atoms in the silicon sample as written in scientific notation? In equation form 3 parts per trillion is written as 1012 A) 3 x 10-12 B)3 x 106 C)3×10-9 D) 3 x 109