One real estate investment has the following characteristics:

A．Annual rental income

B．$18000000

C．Annua operating expenses

D．$1200000

E．Available mortgage rate

F．6%

G．Financing percentage

H．90%

I．Required rate of retum

J．15%

K．Estimated holdng period

L．5 years

M．Investor’s tax rate

N．25%

采集病史时下列最有助于急性心肌梗死诊断的是

A．性别

B．年龄

C．高血压病史

D．胸痛特点

E．诱因