Which of the following is true regarding placenta formation?

Correct option is A

Placenta formation begins around the 6th week of pregnancy and is typically completed by the 12th week. This is when the placenta becomes fully functional in terms of nutrient and waste exchange between the mother and the fetus.
Explanation of options: (a) ✔ Correct. Placenta formation starts at around 6 weeks and is completed by the 12th week, providing necessary functions for fetal development. (b) ✘ Incorrect. Placenta formation begins much earlier and is generally completed well before the 28th week. (c) ✘ Incorrect. Placenta formation does not take until the 36th week to complete. (d) ✘ Incorrect. Placenta formation starts earlier, around the 6th week, and not as early as the 4th week.