7. A Ltd entered into a contract to build bigger premises for B Ltd at a cost of 1,000,000 to allow B Ltd to expand. The work was due to be completed by 18 December 2020. A Ltd got into financial difficulties. To encourage A Ltd to finish the work on time, B Ltd agreed to pay a completion bonus of 200,000. Which of the following is accurate: (a) B Ltd's promise to pay the bonus is unenforceable as there was no offer and acceptance (b) B Ltd's promise to pay the bonus is unenforceable as there was no mutual intention to enter into a legally binding variation (C) B Ltd's promise to pay the bonus is unenforceable as A Ltd did not provide sufficient consideration in return (d) B Ltd's promise to pay the bonus is probably enforceable as it received consideration under the 'practical benefits' principle