The graph below shows the decay of a radioactive isotope. what is the half-life of the isotope?

Is there a graph i can see so i can help you with this question?

As we have mentioned before each radioactive isotope has its own decay pattern. Not only does it decay by giving off energy and matter, but it also decays at a rate that is characteristic to itself. The rate at which a radioactive isotope decays is measured in half-life. The term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. Half-lives for various radioisotopes can range from a few microseconds to billions of years. See the table below for a list of radioisotopes and each of unique their half-lives.

The correct answer is a. we know this because n (hap) + n (hap) = 2n (dip).