The famous mathematician associated with finding the sum of the first $100$ natural numbers is 

Which of the following form of an $\mathrm{AP}$? Justify your answer.

$-1, -1, -1, -1,...$

Which of the following form of an $\mathrm{AP}$? Justify your answer.

$0, 2, 0, 2, ...$

Which of the following form of an $\mathrm{AP}$? Justify your answer.

$1, 1, 2, 2, 3, 3, ...$

Is the sequence $11, 22, 33, ...$ form of an $\mathrm{AP}$? Justify your answer.