Outstanding tax demand u/s. 143(1)/143(3)-self/reg asset ??

Hello everyone,

when i check the status of tax demand of my client following demand is shown

ay             section code         demand

200-08       143(3)                     2000

2008-09         blank                   356

my client has changed the place of residence many times and therefore he did not receive any notice. i think above should be tds credit mismatch difference as per intimation.

my client is ready to pay above demand

my question :

while making payment whether self assessment tax or Tax on regular assessment should be selected ?

waiting for the views of the experts.