Secondary sexual characters are

The correct option is A The features which help to distinguish male from female

• Secondary sexual characters are features that appear during puberty in humans and sexual maturity in other animals. They distinguish the two sexes of a species but are not directly part of the reproductive system.
• Secondary sexual characters common in males and females: Growth of hairs under armpits and around the pubic area, increased activity of sweat and sebaceous glands, oily skin and appearance of pimples, darkening in skin colour of the genital area.
• Secondary sexual characters in male: Widening of shoulders, deepening of the voice, appearance of beard and mustaches. The growth of sex organs (testes and penis).
• Secondary sexual characters in females: Widening of pelvis and hips, high pitch voice, initiation of the menstrual cycle, the growth of mammary glands (breasts), maturation of secondary sex organs like fallopian tubes, uterus.
  

So, the correct answer is 'A'.