The size of the chlorophyll molecule is:

• A
  Head $15 \times 15 \mathring A$,Tail $25 \mathring A$
• B
  Head $20 \times 20 \mathring A$,Tail $25 \mathring A$
• C
  Head $15 \times 15 \mathring A$,Tail $20 \mathring A$
• D
  Head $10 \times 12 \mathring A$,Tail $25 \mathring A$