made easy cbt closed

Question

 how we can solve this type of question?

Comments

How can the answer to the problem be Ω(n^2) because if we take an exaple like here(https://gateoverflow.in/11232/let-f-n-%CF%89-n-g-n-o-n-and-h-n-%D1%B3-n).

Further on solving it gives something like this:-

Let f(n)=An^2+Bn so f(n)=Ω(n) is satisfy , g(n)=Cn+D and h(n)=En 

Now f(n)+g(n)=(An^2+Bn)+(Cn+D)=F(n^2)+G(n)+H⇒Ω(n),O(n^2)

(f(n)+g(n)).h(n)=I(n^3)+J(n^2)+K(n)⇒Ω(n),O(n3) 

Am I correct??