The 2013 annual report of Oracle Corporation included the following information relating to their allowance for doubtful accounts: Balance in allowance at the beginning of the year $323 million, accounts written off during the year of $145 million, balance in allowance at the end of the year $296 million. What did Oracle Corporation report as bad debt expense for the year?

a. $27 million

b. $178 million

c. $118 million

d. $151 million

e. None of the above