Source: KAPLAN

A theorist of modernization in underdeveloped
countries has defined this process as one of
passing from "traditional authority," derived from
long-standing custom and the authority of kinship
leaders, to "legal-rational authority," based on
procedures specifically established for particular
goals. No doubt this scheme works well enough in
categorizing some societies, but how is one to
classify the Ibo society of southeastern Nigeria? In
precolonial Ibo society, village decisions were
reached in general meetings, and formalized by
striking the ground with an ofo, a staff possessed
by the head of a kinship group. This might seem to
fit the theorist's model; but the Ibo altered this
procedure whenever appropriate-for instance, if
the senior kinship head forgot his ofo, any other
ofo could be used. The Ibo, too, freely revised any
customary procedures in order to pursue trade-a
flexibility that served them well in the new capitalist
economy introduced by colonialism. If this
theorist is to be consistent, he must concede that
the Ibo were "modern" before the first colonist
stepped ashore.

The author's primary concern in this passage is to
(A) describe a Nigerian society
(B) reveal a shortcoming in a theory
(C) show how one form of authority gives way to another
(D) explain the interplay of colonialism and capitalism
(E) prove that Ibo society is modern

OA: B

The author mentions the practice of substituting one ofo for another as an example of
(A) the fixity of custom in a traditional authority structure
(B) behavior that does not fit the typology of "traditional authority"
(C) the ability of the theorist's categorization to yield useful insights about society
(D) the Ibos' ability to adapt to a commercial society
(E) the lack of a defined kinship structure in Ibo society

OA: B

I am seeking explanation for these.