Proffering one increasingly improbable scene character after another, (i)___by the constraint of realism, the novel revels in this (ii)___ by ever more brazenly defying its readers' presumed expectations.
A. untrammeled D. exiguity
B. liberated E. ponderousness
C. confined F. implausibility
答案给的是CF, 为什么第一空不选A?