Which one of the following cell types always divide by anticlinal cell division?

1. Fusiform initial cells

2. Root cap

3. Protoderm

4. Phellogen

(d) Phellogen It is secondary meristematic tissue which develops from the cells of cortical region of dicot stem. It is responsible for secondary growth. It's cells divide on both sides, i.e., anticlinal division occurs.
On the outerside of stem, it gives rise to cork or phellem and on inner side phelloderm or secondary cortex.