In teeth with complete pulp necrosis, the periapical area is involved if
1. there is pain to thermal stimuli.
2. there is pain on percussion.
3. the tooth throbs when the patient is lying down.
4. the radiograph shows an apical radiolucency.

(2) and (4)

(1) (2) (3)

(1) and (3)

All of the above.

(4) only