$\displaystyle f(n) \in O(g(n))$ if there is a constant $\displaystyle C$ such that for all $\displaystyle n1 \geq n2$ $\displaystyle f(n) \leq Cg(n)$

Verify that belongs

A) $\displaystyle 8n^2 -3n +2 \in O(n^2)$

B) $\displaystyle 5n-3 \in O(n^2)$