Regulation T Is Set at 50

Regulation T is set at 50%. Bubba's account contains long positions in the following securities with the prices listed
100 ABC $30
200 XYZ $70
200 QBB $40
200 KKK $25
Total market value = $30,000
Debit balance in the account = $12,000
Net equity balance of the account = $18,000
If Bubba wants to buy 100 shares of DUM at $30 per share, how much additional money must be deposited?

A) $3,000
B) $1,500
C) $2,000
D) $0