Respuesta :

The answer is B.  An upward (normal) vector is required to cancel the weight by Newtons 3rd Law.  Otherwise there is a net downward force that would require the book to fall down by F=ma

Since, the book is resting on the table. There is a contact between the surface of the table and the block due to which a normal reaction force will arises, which will be perpendicular to the surface in contact. In this case, the normal force will be opposite to weight of the book and will be equal to its magnitude.

Hence, the option B is correct choice.