[asy]
import cse5;
size(180);
pathpen=black;
pair A1=(0,0), A2=(1,0), A3=(0.5,sqrt(3)/2);
D(MP("A_1",A1)--MP("A_2",A2)--MP("A_3",A3,N)--cycle);
pair A4=(A1+A2)/2, A5 = (A3+A2)/2, A6 = (A4+A3)/2;
D(MP("A_4",A4,S)--MP("A_6",A6,W)--A3);
D(A6--MP("A_5",A5,NE)--A4);
//Credit to chezbgone2 for the diagram[/asy]If △A1A2A3 is equilateral and An+3 is the midpoint of line segment AnAn+1 for all positive integers n, then the measure of ∡A44A45A43 equals<spanclass=′latex−bold′>(A)</span>30∘<spanclass=′latex−bold′>(B)</span>45∘<spanclass=′latex−bold′>(C)</span>60∘<spanclass=′latex−bold′>(D)</span>90∘<spanclass=′latex−bold′>(E)</span>120∘