Induction of the dental follicle is by:

  # Induction of the dental follicle is by:

A. TNF

B. BMP

C. IL1

D. CSF1

The correct answer is B. BMP.

TNF (Tumor Necrosis Factor):  TNF is primarily known as a pro-inflammatory cytokine and is not directly associated with the induction of the dental follicle. 

BMP (Bone Morphogenetic Protein): BMPs are a group of growth factors also known as cytokines and as metabologens. Among their various roles in the body, BMPs are involved in the induction of the dental follicle and play a significant role in bone development and repair. 

IL1 (Interleukin 1): IL1 is involved in inflammatory responses and is not directly associated with the induction of the dental follicle. 

CSF 1 (Colony Stimulating Factor 1): CSF 1 is primarily involved in the control of survival, proliferation, and differentiation of hematopoietic stem cells into macrophages and other related cell types, and it is not directly involved in the induction of the dental follicle. 

Hence, the correct answer is B) BMP, which is involved in the induction of the dental follicle and subsequent formation of the periodontal tissues.