Question

Choose the best way to rewrite the underlined section of the following passage:

The buildings in the court complex were erected whenever money happened to be available. This accounts for the varying architectural styles and the apparent lack of any master plan.
a) The underlined section is correct as is.
b) whenever money happened to be available, this accounts for the varying architectural styles and the apparent lack of any master plan.
c) whenever money happened to be available. This accounts for the varying architectural styles. And the apparent lack of any master plan.
d) whenever

Answer 1

d) whenever money happened to be available this accounts for the varying architectural styles and the apparent lack of any master plan

Answer 2

It's fine as it is. The other sentences are grammatically incorrect.

b. This is a comma splice. A comma splice is a comma placed in a way that attempts to join two independent clauses that need to be separated by an and, a but, a so...etc (these are coordinators). Independent clauses can stand as complete sentences.

c. It's incorrect because the separation of 'This accounts...' from 'And the...' creates an incomplete sentence: And the apparent lack of a master plan (cannot stand alone as a sentence because it's a dependent clause). A dependent clause 'may contain a subject and a verb, but it begins a thought that it doesn't finish' (1)

d. This is just completely wrong because it's a run-on sentence.

(1) Source: http://www.butte.edu/departments/cas/tipsheets/grammar/indep_clause.html