Each of the circles of equal radii with centres A and B pass through the centre of one another. They cut at C and D then ∠DBC is equal to?

Answer: Option C

According to question

AB = AD = DB = r
∴ ΔADB is a equilateral triangle
∠DBA = 60°
Similar in ΔABC
∠ABC = 60°
∠DBC = 60° + 60°
∴ ∠DBC = 120°