Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?
T_ST_S_U_T_S
1). UUSTT
2). TUUTS
3). TTSTU
4). UUTSU
2. Choose the correct order of the given alternative : b _ ab _ b _ aab _ b
3. Choose the correct order of the given alternative : F _ U6 _ 9I _ T7 _ 20 _ 4D23
5. Choose the correct order of the given alternative : 23B _ 6 _ F G _ 5D _ 8 _ H I
6. Choose the correct order of the given alternative : aab _ ab _ cabcca _ bcab _ c
7. Choose the correct order of the given alternative : Z _ 25 Y B 23 X C _ W _ 19 _ E 17