Final answer:
The question involves determining if given signals are bounded and finding the associated bounds for those that are, which involves understanding functions like sine and exponential functions along with step-functions. However, without additional definitions or domain specifications, a precise analysis cannot be provided.
Step-by-step explanation:
The given question requires analyzing different signals to determine whether they are bounded, and for those that are, to find a bound Bx. The signals in question vary with respect to the parameter k, and they utilize mathematical operations such as sine functions, exponents, and step-functions (represented by μ), to describe their behavior. A bounded signal is one that does not grow towards infinity, and a bound Bx can be thought of as a value that the signal does not exceed in magnitude. However, without further information, such as the definition of the step-function μ or the domain of k, it is challenging to provide a complete analysis for each case (a) to (d).