4K curved screen televisions were introduced to the consumer market in April 2014. Led by Korean manufacturers Samsung and LG, prices were high and sales slow for the first two years. Currently, sales are increasing at an increasing rate, they have gained much wider distribution, and new competitors have entered the market. Manufacturers are now realizing profits from the 4K curved televisions, which are in the __________ stage of the product life cycle.
a) growth
b) introduction
c) decline
d) maturity