Let T$($n$)=1/2*$n$^2+3*$n$.$ Which of the following statements are true? $($Choose all that apply.$)$

a$.$ T$($n$)$ in O$($n$^3)$

b$.$ T$($n$)$ in $\backslash$Theta $($n$^2)$

c$.$ T$($n$)$ in $\backslash$Omega $($n$)$

d$.$ T$($n$)$ in O$($n$)$