If you go through the multiplication table of 3, you can pick out the ones between 5 and 31:
6, 9, 12, 15, 18, 21, 24, 27, 30
Which is 9 numbers. I hope this helps!
Answer:
D) t=4d+5
Step-by-step explanation:
If d=1,

If d=2,

If d=4,

Therefore,

Subduction should be added to divergent boundaries