A Shopping Complex Is Considering Building a Self-Service Vending Machine $\mathrm{X} 1$

A shopping complex is considering building a self-service vending machine island. The mall can buy a vending machine for dispensing various types of ready-to-pop corn. Purchase of this machine is captured by variable $\mathrm{X} 1$ , taking a value of 1 and 0 if not purchased. There is also a machine available for popping any type of corn vended by the vending machine. Purchase of this machine is captured by variable X2, taking a value of 1 and 0 if not purchased. If they decide to buy the popcorn popper, then they must have the ready-to-pop corn vending machine. However, if they only buy the ready-to-pop corn vending machine, the customers can take the corn home or pop it in a microwave already available, if the popcorn popper is not purchased. The constraint that implements this will be

A) $X_{1}-X_{2}<$ 0
B) $\mathrm{X}_{1}-\mathrm{X}_{2} \leq$ 0
C) $\mathrm{X}_{1}-\mathrm{X}_{2} \geq$
D) $\mathrm{X}_{1}-\mathrm{X}_{2}=$ 0
E) $X_{1}-X_{2}>$