The correct answer is option 4: Development of breasts in males. Gynecomastia is a condition characterized by the enlargement of breast tissue in males. It occurs due to an imbalance of hormones, specifically an increase in estrogen or a decrease in testosterone levels. This can be caused by various factors such as hormonal changes during puberty, certain medications, liver or kidney problems, obesity, and hormonal disorders. Gynecomastia is not a serious medical condition and often resolves on its own. However, in some cases, it may cause discomfort or embarrassment, and treatment options such as medication or surgery may be considered. It is important to consult a healthcare professional for a proper diagnosis and appropriate management of gynecomastia.