Using only the digits from 0 to 6 , how many 5 digit codes can be constructed, if the first digit can not be 4 and no digits is used more than once ? Choose the correct choice from the following choices:
A) 1800 B) 2160 C) 7776 D) 720 E) 820
5*6*5*4*3= 
<gadget id="calculator">5*6*5*4*3</gadget>
<output>1_800</output>
1800   1800NSWER:1800
<result>A</result>
Using only the digits from 0 to 6 , how many 5 digit codes can be constructed, if the first digit can not be 4 and no digits is used more than once ?