Iridium is an element that is rare on Earth but commonly found in meteorites. A scientist believes that the first organic molecules may have come to Earth on meteorites 3.6 billion years ago. Which of these would be an appropriate null hypothesis to test related to whether meteorites hit the Earth 3.6 billion years ago?

If sediment layers that are 3.6 billion years old are tested, they will contain relatively high iridium levels, because that is when many meteorites crashed into the Earth.
A

There is no difference in iridium levels in sediments that were deposited on Earth 3.6 billion years old, compared to recent sediments.
B

If a sediment layer that is 3.6 billion years old is tested, it will contain organic material.
C

If recently fallen meteorites and meteoroids collected in space are tested, they will not contain organic molecules.