Movement into and out of cells — practice question

Which sequence of events could result in mass flow in a phloem sieve tube?

• A$1 \rightarrow 2 \rightarrow 5 \rightarrow 6 \rightarrow 4 \rightarrow 3$
• B$3 \rightarrow 1 \rightarrow 2 \rightarrow 5 \rightarrow 6 \rightarrow 4$
• C$3 \rightarrow 5 \rightarrow 1 \rightarrow 2 \rightarrow 4 \rightarrow 6$
• D$5 \rightarrow 2 \rightarrow 1 \rightarrow 4 \rightarrow 6 \rightarrow 3$