 Complete the following phrase:  The 133rd CB and the 4th Marine Pioneer Battalion were the primary units of the Assault shore parties for the 23rd and 25th Regimental Combat Teams RCT on the 4th Marine Divisions yellow and blue beaches. The 4th Marine Divisions single Pioneer Battalion was assigned to the 25th RCT. USMC tactical operations required another Pioneer battalion for the 23rd RCTs Assault. The 121st CB had been tasked as such at Roi-Namur, 