Which is most likely the reason why there were no pink colonies seen on spread plate d?

Here are the missing options for the above question:
1. The bacterial culture in test tube D was diluted so much that no pink bacteria were left in the sample.

2. The pink bacteria were not able to get enough energy from the nutrient broth in test tube D to live.

3. The white bacteria outcompeted the pink bacteria for the nutrients in the broth in test tube D.

4. The pink bacteria are sediment growers in nutrient broth and the micropipette could not reach them.

It was about Spread Plate Method of Isolation with nutrient broth. Therefore the best answer choice is:

1. The bacterial culture in test tube D was diluted so much that no pink bacteria were left in the sample.