Passage: Foch planned a series of concentric attacks on the German lines in France (sometimes referred to as the Grand Offensive), with the various axes of advance designed to cut German lateral communications, intending that the success of an attack would enable the entire front line to be advanced. The main German defences were anchored on the Hindenburg Line, a series of defensive fortifications stretching from Cerny on the Aisne river to Arras. Before Foch's main offensive was launched, the remaining German salients west and east of the line were crushed at Havrincourt and St Mihiel on 12 September and at the Battle of Épehy and the Battle of the Canal du Nord on 27 September.The first attack of the Grand Offensive was launched on 26 September by the French and the AEF in the Meuse-Argonne Offensive (this offensive includes the Battle of Somme-Py, the Battle of Saint-Thierry, the Battle of Montfaucon, and the Battle of Chesne of 1 November). The offensive involved attacking over difficult terrain, resulting in the Hindenburg Line not being broken until 17 October. Two days later, the Army Group under Albert I of Belgium (the Belgian Army, the British Second Army and the French Sixth Army), attacked near Ypres in Flanders (the Fifth Battle of Ypres).  Both attacks made good progress initially but were then slowed by supply difficulties.

Question: Which groups were under the control of Albert I?
the Belgian Army, the British Second Army and the French Sixth Army