6: Which of the following is the general solution of some differential equation of the form y'"+ by" + cy' + dy = 0, where b, c, d are real constants? (i) C1 cost + C2 sint + C3 (ii) C1 + C2t + C3(5t + 1) (iii) Chest cos(2t) + C2est sin(2t) (A) (i) only (B) (i) and (ii) only (C) (ii) and (iii) only (D) (iii) only (E) all of them (F) none of them (G) (ii) only (H) (i) and (iii) only Select v