The lower portions of the 2008 income statement for duke Energy Corporation follows (dollars in millions, except per-share amounts):

Income from continuing operations .......... $1,279

Income from discontinued operations, net of tax ...... 16

Income before extraordinary items .......... 1,295

Extraordinary items, net of tax ............ 67

Net income .................. $1,362

Earnings per share for continuing operations

Basic ..................... $1.01

Diluted ..................... $1.01

Earnings per share from discontinued operations

Basic ..................... $0.02

Diluted .................... $0.01

Earnings per before extraordinary items

Basic ..................... $1.03

Diluted .................... $1.02

Earnings per share from extraordinary items

Basic ..................... $0.05

Diluted ..................... $0.05

Earrings per share

Basic ..................... $1.08

Diluted ..................... $1.07

Required

(a) Why is there a distinction among income from continuing operations, income from discontinued operations, and income from extraordinary items?

(b) Estimate the number of common shares outstanding

(c) Why is there a distinction between basic earnings per share and diluted earnings per share?

(d) Estimate the number of common shares that would be outstanding if all potentially dilutive securities were converted to common shares.