If a Solution with Time Complexity $\varTheta$ (N²) Is Known to Exist, Then the Problem Is Known

Multiple Choice

If a solution with time complexity $\varTheta$ (n²) is known to exist, then the problem is known to be in which of the following?

A) $\varTheta$ (n²)
B) O(n²)
C) $\varTheta$ (n³)
D) $\varTheta$ (n)