The cross-section of a long thin-walled member is as shown in the figure. When subjected to pure twist, point $\mathrm{A}$
(A) does not move horizontally or axially, but moves vertically
(B) does not move axially, but moves both vertically and horizontally
(C) does not move horizontally, vertically or axially
(D) does not move vertically or axially, but moves horizontally
The cross-section of a long thin-walled member is as shown in the figure. When subjected to pure twist, point $\mathrm{A}$
(A) does not move horizontally or axially, but moves vertically
(B) does not move axially, but moves both vertically and horizontally
(C) does not move horizontally, vertically or axially
(D) does not move vertically or axially, but moves horizontally
(A) does not move horizontally or axially, but moves vertically
(B) does not move axially, but moves both vertically and horizontally
(C) does not move horizontally, vertically or axially
(D) does not move vertically or axially, but moves horizontally