While taking measurements using a theodolite, the following errors occurred:
1. Error due to inaccurate centering
2. Error due to inaccurate leveling
3. Error due to imperfect graduations
4. Error due to improper use of tangent screws
Which of the above is/are not a type of personal error?
1
3 only
2
1 and 4 only
3
1 and 2 only
4
3 and 4 only