BR Piling Pte Ltd was contracted to install bored piles and construct a basement carpark for a 13-story building in Singapore. The piling contractor completed the works and handed the site to the architect by the stipulated deadline. The architect was engaged by the owner and was responsible for the design and supervision of works for the entire project. Two weeks later, the project's superstructure work was awarded to another contractor, KC Contractors at a lump sum price of $25 million using the SIA Lump Sum contract (9th Edition). The contract duration is 12 months commencing from 1st Jan 2020. (a) During the site handover, KC Contractors found out that the basement slab level constructed by BR Piling was 100mm lower than what was required in the approved construction drawings. KC Contractors then informed the architect that topping up with concrete to the required basement slab level was necessary and submitted a quotation of $100,000 for the additional work. KC Contractors also refused to take over the site until the variation cost was approved. The architect called for a site investigation. The result showed that it was an error caused by BR Piling Pte Ltd's land surveyor. Discuss the options available to the architect including the implications.