In a(n) like the kidney, several kinds of tissues work together.

The correct answer would be the organ.

In the cellular organization, the organ is defined as the collection or group of tissues which are adapted to perform a specific function.

For example, kidney, heart, liver et cetera.

In higher organisms, different organs work in synchronization to form an organ system.

For example, kidneys, ureters, urinary bladders are the part of an excretory system.

looks like the answer is     c     to me!

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.