Physics Work,Power & Energy Level: Misc Level

A block of mass M is placed on a plane of length L which is inclined at an unknown angle with respect to the horizontal. There is friction between the block and the surfaces, so a gentle nudge is required to start the block moving. Assume this nudge is sufficiently gently so that the initial speed of the block is zero.When the block reaches the bottom of the incline, it slides along the table top until coming to rest a distance L from the bottom of  the incline.a) What is the work done by the normal force that the plane exerts on the block? b)What is the work done by gravity during the entire motion? c)How is the work done by friction during the entire motion related to the work done by gravity?  Explain all reasoning.