Detailed Instructions: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Problem:Question: When we inject 1 nanoliter (nL) sample we are referring to the injection of:
Options: <1> 10-1 L. <2> 10-3 L. <3> 10-6 L. <4> 10-9 L. <5> 10-12 L.
Solution:
4