The correct option is B Increased activity of sweat and sebaceous gland
In girls and boys, there are various changes that take place during puberty. One of them is the effect of increased amounts of androgen. The androgen causes an increased secretion of oil or sebum from the skin and the resultant oil causes variable amounts of acne. Also, rising levels of androgens can change the fatty acid composition of perspiration, resulting in a more 'adult' body odour.