EDITED
point b) well lets see. Boys a has a choice to date girl A (age 23) or girl B (age 19) if he is encouraged to date girl A then girl B just lost out on a date. pretty simple formula.
this goes as well for point C). some R”Y are grappling with this issue. To what degree should they encourage a boy to date girl A knowing full well it will mean less dates for girl B. Clearly the 70 R”Y who signed on the letter as well as many others have stated thier opinion on the matter but as with everything else there are varying degrees.