Which satellite system helps to connect remote region, vehicles, ships, people and aircraft to other parts of the world and/or other mobile or stationary communications units, in addition to serving as navigation systems.

Question

$\begin{array}{1 1} (a)\; \text{Fixed satellite system} \\ (b)\; \text{Mobile satellite system} \\ (c)\; \text{Space satellite system} \\ (d)\; \text{Scientific research system} \end{array}$