File 12ab contains one of the two Introits and the Responsorial Psalm.
INTROIT - 12a OR 9m (same as Christmas, Mass at Dawn)
RESPONSORIAL PSALM - 12b
ALLELUIA - 11f (same as Holy Family, for use with the ad libitum Year B readings)
OFFERTORY - 12c
COMMUNION - 9p (same as Christmas, Mass at Dawn)