A software development effort was estimated to address 10 requirements, with 1K SLOC per requirement, a 60% ESLOC conversion factor, and 1.0 hrs/ESLOC productivity, for a total effort of 6,000 hours. Over the course of development, 2 additional requirements were added; 1.5K SLOC were needed to address each requirement; the ESLOC conversion factor rose to 80%; and final productivity was 1.1 hrs/ESLOC, resulting in a total effort of 15,840 hours. What was the cost growth factor due to Reuse optimism (independent of other factors)?

a 1.10

b 1.50

c 1.33

d 1.20