The correct option is A 1st
The heart of the foetus develops after one month of pregnancy and the beats can be heard using stethoscope.
By the end of second month, limbs and digits develop.
By the end of third month or the first trimester, all the major organs are formed.
By fifth month, fetus starts to move around. Hair appears on head.
By the end of second trimester, body is covered by fine hair, eye lids separate and eye lashes are formed.
By the end of ninth months, the foetus is fully developed and ready to be delivered.