Answer:
B.29
Step-by-step explanation:
In general purpose acme thread:
Nominal depth of thread=0.5

Included angle =29 degrees
Generally Acme thread are following types
1.General purpose(G) Acme
2.Centralizing(C) Acme
3. Stub Acme
Centralizing(C) Acme threads have tighter tolerance during manufacturing as compare to General purpose(G) Acme threads.