Task: Text Categorization
Input (English): Question: Why do ovarian cycles not appear in nursing mothers for several months after birth ?: 
 Options:  <0> For stress and lack of sleep associated with breastfeeding. <1> Because there are low levels of FSH and LH. <2> Because there are high levels of oxytocin. <3> By saving iron that is derived from breastfeeding. <4> Because there are high levels of progesterone.
Output (English): pharmacology