Recommend and justify the type of survey mode for the following cases:

a. Super-Juice would like to test a fruit-based smoothie and a dairy-based smoothie.

b. Super-Connection, a telecommunications company, requires information on the degree to which its post-paid customers are satisfied with the services provided.

c. Clean-Pro is considering a vacuum cleaner with new mopping functions and wants to know people’s reaction to it.

d. The Residents’ Committees (RCs) has received numerous complaints about irresponsible security guards and noisy neighbors and wants to know how to resolve these problems.