XVIII Reserve Corps (German Empire)
Structure on formation

Corps
Division
Brigade
Units
XVIII Reserve Corps
21st Reserve Division
41st Reserve Infantry Brigade
80th Reserve Infantry Regiment
XVIII Reserve Corps
21st Reserve Division
41st Reserve Infantry Brigade
87th Reserve Infantry Regiment
XVIII Reserve Corps
21st Reserve Division
42nd Reserve Infantry Brigade
81st Reserve Infantry Regiment
XVIII Reserve Corps
21st Reserve Division
42nd Reserve Infantry Brigade
88th Reserve Infantry Regiment
XVIII Reserve Corps
21st Reserve Division
-
7th Reserve Dragoon Regiment
XVIII Reserve Corps
21st Reserve Division
-
21st Reserve Field Artillery Regiment
XVIII Reserve Corps
21st Reserve Division
-
4th Company, 11th Pioneer Battalion
XVIII Reserve Corps
21st Reserve Division
-
21st Reserve Divisional Pontoon Train
XVIII Reserve Corps
21st Reserve Division
-
17th Reserve Medical Company
XVIII Reserve Corps
25th Reserve Division
49th Reserve Infantry Brigade
116th Reserve Infantry Regiment
XVIII Reserve Corps
25th Reserve Division
49th Reserve Infantry Brigade
118th Reserve Infantry Regiment
XVIII Reserve Corps
25th Reserve Division
50th Reserve Infantry Brigade
168th Infantry Regiment
XVIII Reserve Corps
25th Reserve Division
50th Reserve Infantry Brigade
83rd Reserve Infantry Regiment
XVIII Reserve Corps
25th Reserve Division
-
4th Reserve Dragoon Regiment
XVIII Reserve Corps
25th Reserve Division
-
25th Reserve Field Artillery Regiment
XVIII Reserve Corps
25th Reserve Division
-
1st Reserve Company, 11th Pioneer Battalion
XVIII Reserve Corps
25th Reserve Division
-
2nd Reserve Company, 11th Pioneer Battalion
XVIII Reserve Corps
25th Reserve Division
-
25th Reserve Divisional Pontoon Train
XVIII Reserve Corps
25th Reserve Division
-
18th Reserve Medical Company
XVIII Reserve Corps
Corps Troops
-
18th Reserve Telephone Detachment
XVIII Reserve Corps
Corps Troops
-
Munition Trains and Columns corresponding to the III Reserve Corps

Question: How many Infantry Regiments were included in the XVIII Reserve Corps, and what is the number of the regiment?
Answer: XVIII Reserve Corps included one Infantry Regiment (168th).