What is the accepted size of a chlorophyll molecule?

• A
  Head: $15 \times 10 \ \mathring{A}$ and Tail: $25 \ \mathring{A}$
• B
  Head: $20 \times 20 \ \mathring{A}$ and Tail: $25 \ \mathring{A}$
• C
  Head: $10 \times 10 \ \mathring{A}$ and Tail: $15 \ \mathring{A}$
• D
  Head: $15 \times 15 \ \mathring{A}$ and Tail: $20 \ \mathring{A}$