The sentence refers to the metaphorical idea that true friends of an organization may appear in various forms or "garbs" (ways of presenting themselves). The correct phrase should mean "wearing" or "covered in" different appearances, either literally or figuratively.
The term "clad in" means "covered in" or "wearing" and is often used in both literal and figurative contexts. Here, "clad in different garbs" suggests that these friends may take on different roles, styles, or appearances while still holding genuine intentions.
Option (a) "come in" could fit grammatically but lacks the strong descriptive imagery of being "covered" in something.
Option (c) "dressed in" is similar in meaning to "clad in" but is less formal and less literary in tone; "clad in" matches the elevated tone of the sentence.
Option (d) "clothed in" also means "wearing," but it is typically used in more literal, physical clothing contexts rather than figurative expressions.
Therefore, "clad in" is the most precise and stylistically appropriate choice here.