According to the NCERT text, the obvious answer to 'Why MTP?' is to get rid of unwanted pregnancies either due to casual unprotected intercourse or failure of the contraceptive used during coitus or rapes. MTP is also used when the continuation of pregnancy is harmful. Option 1 is incorrect because MTP to get rid of a female child (female foeticide) is illegal. Option 4 is incorrect because while MTP plays a role in population decrease, it is not the primary aim/practice reason stated in the text.