Think of an LCA study as answering four questions in sequence: why and for what are we studying this (goal and scope), what goes in and comes out (inventory), what harm does that cause (impact assessment), and what does it all mean (interpretation). The reference basis used throughout the whole study, the functional unit such as $1$ tonne of product or $1$ m$^3$ of treated water, is fixed while setting the goal and scope, so both "determination of functional unit" and "defining goal and scope" belong to the same, first LCA phase. Compiling the list of every material and energy input together with every emission and waste output for each process step is exactly the life cycle inventory phase, so "listing out inventory of inputs and outputs" is also a genuine LCA step. "Technology readiness level" is a completely separate concept from research and technology management circles, used to rate how close a technology is to commercial deployment; it has no place in the ISO 14040 LCA methodology. Removing the odd one out leaves the functional unit, the goal-and-scope definition and the inventory listing as the true LCA-associated options.
\[\boxed{\text{Correct options: A, B, D}}\]