First evidence of calcification of deciduous incisors is at:

 # First evidence of calcification of deciduous incisors is at:

A. 2 months 

B. Between 1 to 2 months

C. 30 weeks in utero 

D. 11 weeks in utero

The correct answer is D. 11 weeks in utero.

According to "Developmental Dentistry" by J.R. Rooper and A.M. Foreman, the calcification of deciduous incisors begins at around 11 weeks in utero, followed by the development of other teeth in a specific sequence over the subsequent weeks and months of fetal development.