A man and a woman who do not show any apparent signs of certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters is affected. Which of the following modes of inheritance, for this disease.

The correct option is B Sex-linked recesive
Sex-linked diseases are passed down through families through either X or Y chromosomes. X and Y are the sex chromosomes. Dominant inheritance occurs when an abnormal gene from one parent which is dominant causes the disease, even though the matching gene from the other parent is normal.
The term "sex-linked recessive" most often refers to X-linked recessive. In the case of females, the recessive inheritance is caused when both matching genes must be abnormal to cause disease. If only one gene is abnormal then the female is a carrier and she is unaffected without symptoms. Carriers can pass abnormal genes to their children. While sons have only one X chromosome and they receive the X chromosome from their mother, so there are high chances of them being affected.