Consider the following two classification task,

$1.$ Covid disease prediction

$2.$ Spam email prediction

For each of the above tasks answer the following question.

A$.$ What is the effect on precision and recall if FP and FN are zero?

B$.$ Which out of FP$=0$ and FN$=0$ is desirable for both the above$-$mentioned classification task.

C$.$ For both tasks, if you optimize between precision and recall, which one will you optimize?

D$.$ Two different model performance on train dataset is shown as below for the covid prediction task. Which model is best suited? Justify your answer.