Final answer:
Improved laundry detergent is the best example of a continuous innovation among the listed options, as it represents a slight improvement of an existing product without altering consumer behavior markedly.
Step-by-step explanation:
Out of the options listed, improved laundry detergent represents the best example of a continuous innovation. This type of innovation involves a slight modification of an existing product rather than the introduction of a completely new concept. Improved laundry detergent reflects an enhancement of existing products and fits into consumers' existing habits and routines without requiring them to learn new behaviors. On the contrary, products like digital cameras, smartphones, and personal computers represented more discontinuous or disruptive innovations, as they introduced significant changes in technology or consumer behavior when they were first introduced.