Consider the following modifications regarding avoiding the interference between gears:
1. The centre distance between meshing gears be increased
2. Addendum of the gear be modified
3. Teeth should be undercut slightly at the root.
4. Pressure angle should be increased
5. Circular pitch be increased
Which of these are effective in avoiding interference?
(a) 1, 2 and 3 (b) 2, 3, 4 and 5
(c) 1, 4 and 5 (d) 3, 4 and 5