Error in formation. Humans have 23 pairs of chromosomes. During the formation of the egg, each pair splits and one of each travels to the egg. At conception, the sperm brings 22 + an X or Y & the new embryo now has 23 pairs (two of each). In Kleinfelter, the egg retains 2 X chromosomes instead of 1 & the sperm brings a Y.The fetus then has 23 pairs + the extra X. This is an error in formation, not an inherited trait.
Neither. My colleagues have explained this well. It's not even inherited. If you were given this question in class by a teacher, bring it to the attention of the teacher's supervisor.
Neither. Klinefelter syndrome is caused by error in paternal or maternal meiosis.
Klinefelter. Klinefelters is a genetic disease caused by what is called "nondisjunction". Every male inherits an x chromosome from their mother and a y chromosome form their father making an xy male. Patients with klinefelters have an extra x chromosome and are thus XXY males.