Which is the best job offer and why/why not?

• a. $60,000 starting salary with a 401k retirement (3% match)
• b. $50,000 starting salary, $15,000 sign-on bonus, with a 401k retirement (4% match)
• c. $40,000 starting salary, $20,000 in stock options paid over 4 years
• d. $35,000 starting salary, 5% equity in the company, 5,000 shares when the company goes public in 2 years