The following are National Accounts data for a particular year.

$ million
Gross Domestic Product 4,000
Consumption Expenditure 2,400
Government Expenditure 700
Gross Taxes 900
Exports 900
Gross Operating Surplus 2,000
Government Interest Payments 100
Transfer Payments 300
Imports 800
Business Fixed Investment 900

The level of public saving is:
a. $200m
b. -$100m
c. -$200m
d. -$700m
e. zero