Consider the following statements regarding mitochondria and choose the correct answer:
1. Mitochondria are present in all cells which respire aerobically
2. They are absent in bacteria, where the plasma membrane has respiratory enzymes
3. Cells with high metabolic activity have a high number of mitochondria

A. Only 1 and 2 are correct

B. Only 2 and 3 are correct

C. Only 3 is correct

D. 1, 2 and 3 are correct

Answer: Option D