The following diagram shows the branching tree diagram for some animals.

A slanting line is shown. There are five lines drawn vertically on this line at equal intervals. Shark, Frog, Kangaroo, Lion and Chimpanzee are written on top of each vertical line in order from left to right. Common Ancestor is written on the left end of the line. There is a black circle between each pair of these vertical lines. The first black circle is before Shark and says Vertebrae. The second black circle is between Shark and Frog and says Lungs. The third black circle is between Frog and Kangaroo and says Mammary gland. The fourth black circle is between Kangaroo and Lion and says Placenta. The fifth black circle is between Lion and Chimpanzee and says Large brain.

Which two organisms share the least number of derived characteristics?

Frog and kangaroo
Kangaroo and chimpanzee
Lion and chimpanzee
Shark and chimpanzee