Why Might Information on Homosexuals Taken from Reports by the National

Why might information on homosexuals taken from reports by the National Survey of Family Growth (NSFG) be inaccurate?

A) The NSFG asked nonequivalent questions on behavior to males and females,making gender comparisons inaccurate.
B) The NSFG used unsystematic and unscientific sampling techniques while selecting its participants.
C) The NSFG discounted the experiences of women as irrelevant,thus excluding half the population.
D) The NSFG discounted the experiences of men as irrelevant,thus excluding half the population.