How to create internal choice

[Sydykov Almaz]

Dear all,
My data is as follows. Respondents were asked 5 times.
I am new to Stata and I am in trouble with data management. I need to create an Internal choice between A and B . But for some respondents, there are empty cells because they already clearly preferred choice A to choice B or vice-versa. Please help me with Stata commands.
I would appreciate any help.

record_id	trial	alternative	Do you like A ?(yes=1/no =2)	Do you like B? (yes=1/no =2)	Which of them do you prefer A=1/B=2	Do you like A ?(yes=1/no =2)	Do you like B? (yes=1/no =2)	Which of them do you prefer A=1/B=2	Do you like A ?(yes=1/no =2)	Do you like B? (yes=1/no =2)	Which of them do you prefer A=1/B=2	internal
4	1	1	1	1	1	1	1	1	1	1	2	1
4	1	2	1	1	1	1	1	1	1	1	2
4	2	1	1	1	1	1	1	1	1	1	2	1
4	2	2	1	1	1	1	1	1	1	1	2
4	3	1	1	1	1	1	1	1	1	1	2
4	3	2	1	1	1	1	1	1	1	1	2
4	4	1	1	1	1	1	1	1	1	1	2
4	4	2	1	1	1	1	1	1	1	1	2
4	5	1	1	1	1	1	1	1	1	1	2
4	5	2	1	1	1	1	1	1	1	1	2
7	1	1	2	2	2	1	2		2	1
7	1	2	2	2	2	1	2		2	1
7	2	1	2	2	2	1	2		2	1
7	2	2	2	2	2	1	2		2	1
7	3	1	2	2	2	1	2		2	1
7	3	2	2	2	2	1	2		2	1
7	4	1	2	2	2	1	2		2	1
7	4	2	2	2	2	1	2		2	1
7	5	1	2	2	2	1	2		2	1
7	5	2	2	2	2	1	2		2	1

[William Lisowski]

Reposted at https://www.statalist.org/forums/for...nternal-choice with subsequent discussion there.