Hello,
There would be no problem if you forgot to choice lock before the final date of JAC Delhi counseling. The last saved choices of yours will be locked automatically.
However if you didn't select any choice then the JAC won't have anything to alot to you and hence you won't be able to get any college through the counseling.
For more details you can refer to the following link
https://engineering.careers360.com/articles/jac-delhi-counselling
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