When preparing a post space in a figure-8 shaped premolar, which of the following is/are appropriate?
1. Use one post in the straightest canal.
2. Achieve post fit between the mesial and distal walls of the straightest canal.
3. Extend core material 2mm apically in the nonposted section of the figure-8.
4. Remove tooth structure to make an oval shaped canal.

(1) (2) (3)

(4) only

(2) and (4)

(1) and (3)

All of the above.