Le is used for a masculine word, La is used for a feminine word, and L' is used in a situation where the first letter of the next word is a vowel. (eg. "the education" ; "l'éducation"). Sorry, Im not sure about COD and COI </3
Answer:
Lui is used for a singular person, and Leur is for plural. They're used for indirect responses and are used after "à"
Step-by-step explanation: