The correct structure of the product 'A' formed in the reaction

The structure of the product formed in the reaction given below is :

The structure of the product formed in the reaction given below is :

The product formed in the reaction, Product is

The product formed in the reaction, Product is

The correct structure of product, D formed in the following sequence of reactions is

Write the name and draw the structure of the product which is formed by the reaction of formaldehyde and ammonia.