Roberto Designers was organized on January 1, 2018. The firm was authorized to issue 160,000 shares of $6 par value common stock. During 2018, Roberto had the following transactions relating to stockholders' equity: Issued 16,000 shares of common stock at $8 per share. Issued 32,000 shares of common stock at $9 per share. Reported a net income of $160,000. Paid dividends of $80,000. Purchased 3, 500 shares of treasury stock at $11 (part of the 32,000 shares issued at $9). What is total stockholders' equity at the end of 2018?
a. $416,000
b. $457, 500
c. $576,000
d. $489, 500