Lula most likely complains about scout and jem's presence at her church because
a)she knows the finch children misbehave
b)she distrusts white people
c)she feels her space is being threatened
d)she thinks more white people will come to the church after this

I think the closest possible answer to this question is A)she knows the Finch children misbehave.
Conscious of church guidelines, Lula wants the couple to be able to control their children during mass
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In stockton people love to commit crime it's what we best at doing