IMHO D
A) that the Roman Catholic Church formally proclaimed in 1854, not referring to the conception of Jesus, which, according to Christianity, occurred miraculously despite his mother Mary being a virgin, but to the conception of Mary in the womb of her mother, Anne, despite the factthat they believe this conception occurred with
the antecedent of "they" is not clear
(B) that the Roman Catholic Church formally proclaimed in 1854, did not refer to the conception of Jesus, that,
...
A) that the Roman Catholic Church formally proclaimed in 1854, not referring to the conception of Jesus, which, according to Christianity, occurred miraculously despite his mother Mary being a virgin, but to the conception of Mary in the womb of her mother, Anne, despite the factthat they believe this conception occurred with
the antecedent of "they" is not clear
(B) that the Roman Catholic Church formally proclaimed in 1854, did not refer to the conception of Jesus, that,
...
