Part $2$ of $3-$ Drinking Straw Rotation

After the drinking straw is completely inserted, the juicebox with straw are moved to a vertical position. Once the fluid motion stops, a child begins to rotate the straw at an angular velocity, $.$

Question $6$ of $9$

Mark each of the following which would be appropriate spatial boundary conditions to properly model the motion inside the straw.

A$.$ At $t=0,v_{}=0.$

B$.$ At $r=R,v_{}=R.$

C$.$ As $r$ infinity, $v_{}=0.$

D$.$ At the center of the straw, the flow is symmetric. Thus, at $r=0,$del$\frac{r{v}_{}}{d}$elr$=0.$

E$.$ None of the above.