An electric field-line diagram for two isolated point charges shows twelve lines leaving charge A and four lines entering charge B. No other lines are present. Which of the following statements is most consistent with the information conveyed by the diagram?
a) Charge A is positive and has three times the magnitude of the positive charge B.
b) Charge A is positive and has three times the magnitude of the negative charge B.
c) Charge A is positive and has four times the magnitude of the negative charge B.
d) Charge A is negative and has three times the magnitude of the positive charge B.