Ans. is 'b' i.e., Secondary sexual characters before the age of 6 years o Precocious puberty is the appearance of appropriate secondary sexual characters before the age of 8 years and occurrence of menstruation before 10 years of chronological age.o It is divided into the following types:A) Gonadotropin dependent precocious puberty/ Central precocious puberty / True precocious puberty:# Most common cause is constitutional, due to early maturation and activation of the hypothalamic - pituitary - gonadal axis.# Both breast and pubic hair development in girls# Pubic hair development and testicular enlargement in boys# Early developing sexual characteristics are "isosexual", meaning they are consistent with the child's gender.# Initial spurt in the height followed by premature closure of epiphysis with the result the ultimate height remains stunted.B) Gonadotropin - independent precocious puberty/ Peripheral precocious puberty/Pseudo - precocious puberty:# Exposure to sex steroid hormones that derive from the gonads, the adrenals or the environment.# Further subclassified as isosexual when sexual characters are consistent with gender, and as contrasexual when inconsistent with gender (virilization in girls, or feminization in boys).# Autonomous functional ovarian follicular cysts are the most common cause of gonadotropin - independent precocious puberty in girls.C) Incomplete precocious puberty':# Children with isolated premature thelarche or premature adrenarche. Both usually represent variants of normal pubertal development, but some will progress to complete precocious puberty that may be gonadotropin - dependent or independent.