What is the difference between a flighting schedule and a pulsing schedule?

a$)$ Flighting involves alternating periods of heavy advertising with periods of no advertising, while pulsing involves maintaining a consistent level of advertising throughout the campaign.

b$)$ Flighting involves maintaining a consistent level of advertising throughout the campaign, while pulsing involves alternating periods of heavy advertising with periods of no advertising.

c$)$ Flighting and pulsing are two terms for the same scheduling strategy.

d$)$ Flighting and pulsing are both scheduling strategies used only in digital advertising.