a) The whole problem
b) Your Definition to a problem
c) Problem you design
d) Representing your problem with variable and parameter

Answer: d
Explanation: Because state space is mostly concerned with a problem, when you try to solve a problem, we have to design a mathematical structure to the problem, which can only be through variables and parameters. eg. You have given a 4-gallon jug and another 3-gallon jug. Neither has measuring marker on it. You have to fill the jugs with water. How can you get exactly 2 gallons of water in to 4 gallons. Here the state space can defined as set of ordered pairs integers(x,y), such that x=0,1,2,3 or 4 and y=0,1,2 or 3; X represents the number of gallons in 4 gallon jug and y represents the quantity of water in the 3-gallon jug.