The term 'mattress option' refers to two different types of mattresses: a KING size mattress and a FIRM mattress. A KING size mattress is the largest standard mattress size, measuring 76 inches wide by 80 inches long. It is ideal for couples or those who need extra space to sleep comfortably. A FIRM mattress is a type of mattress that provides more support than a traditional mattress, making it a good choice for those who suffer from back pain or other aches and pains.