Suppose that u₁ (t) and u₂(t) are both solutions to the equation u"" - u' +4u=t². Which of the following are also solutions? ○ 글1 (t) + 호라2 (t) O 3u₁ (t)- 2u2(t) Oui (t) + 2u2(t) O None of the answers are solutions to the equation. O 5u₁ (t)