Jeremy Founded a Company

Jeremy founded a company. He issues 100,000 shares of series A stock for his own $100,000 investment. He then goes through three further rounds of investment, as shown below: Round Price Number of Shares
Series B $1.00 500,000
Series C $1.50 300,000
Series D $1.75 500,000
Which of the following is closest to the percentage of the company owned by the series D investors?

A) 29%
B) 36%
C) 39%
D) 54%