For the second example, the expression is “avoir le droit à qqc”.  https://www.wordreference.com/fren/avoir

Where does your first example come from ? I don’t see it in the lesson. 

I would use ‘choisir .. un cadeau pour qqn’. There are many examples of ‘un cadeau pour qqn’ on French gift vendors’ sites, but I haven’t found any of ‘un cadeau à qqn’, except if required by the verb form eg faire un cadeau à, donner un cadeau à, acheter un cadeau à (in this case - to buy from). 

This is not the situation in your example as the verb form is not ‘choisir… à NOUN’, and with a verb, it would be ‘choisir de INFINITIVE’ 

https://www.lawlessfrench.com/grammar/verbs-with-a/    https://www.lawlessfrench.com/grammar/verbs-with-de/

Hi Priyanka 

à is a preposition taking the meaning "to" or "for" in English according to context.

choisir un cadeau à qqn. -- to choose a present to someone
avoir le droit à qqc. -- to have the right to something

Chris - do you have a reference for "choisir un cadeau à chacun...".  Collins English-French translator site gives '....pour chacun . .' (both for 'for each' and 'to each'),  while using "à chacun" with offrir, donner, faire. 

It may be that both forms are correct or there is disgreement, as at least some native speakers I know would use 'choisir pour . .'

Hi, thank you for helping me out with my query. I was wondering if 'pour' could be used instead of à. Many times à is used in sentences that would mean for in English. So, if someone could help me out with when à can be used and when pour can be used. Merci beaucoup!

@Maarten: It's definitely something I haven't heard used often. To my ears, it sounds like "to choose a gift to someone" as opposed to "for someone". Doesn't work well in English, I know.It would be helpful to know the entire sentence and where it comes from.

Bonjour,

Merci pour votre réponse. C'est une instruction d'exercice dans un livre intitulé Synchronie-1, Leçon 3.  It is an exercise instruction in a book called Synchronie-1, Leçon 3. 

So this exercise asks you to associate a gift with each person. Now this makes a lot more sense! Context is everything.