Please explain legal principles, arguement, applications and conclusion.

Question 1 Laris Supermarket (LM) was about to be opened and the management was looking to install a security system. ERT Sdn Bhd carried out a business in supermarket security system. Abu, a general manager at LM told Ali, his friend who is also a manager at ERT Sdn Bhd that he needs to install the best security system at LM. Ali was told to install CCTV system at cashiers' areas and sales floor, using the best technology. Abu has requested a quotation from Ali's company. ERT sent the quotation and had asked LM to mark the type of the equipment/ system needed and to return the documents to ERT Son Bhd. LM had marked the system Pelco but the document was never received by ERT Sdn Bhd because the staff at LM had sent the document to ERT Sdn Bhd's old address. ERT San Bhd nevertheless could not wait and went to LM and installed Sony system in all areas of the supermarket including the warehouse. ERT San Bhd chose Sony system because the company thought the system was the best due to its highest price. When ERT San Bd presented the bill, LM refused to pay. Discuss in relation to whether a contract existed between ERT Sdn Bhd and LM