There isn't really enough information to answer your questions. Snapping out answers like C# is dangerously bad given your questions. Almost all of your numbered points have nothing to do with the language you use.
Here are my questions in return as most large orgs don't have a single language:
1. Where are you located? This matters for finding people with the skills you will need.
2. What is the eco-system of your current organization?
3. What business is your organization in? Can you utilize shrink-wrapped packages like SAP?
4. Does your IT department write a lot of software? Ours not only writes software for our customers, but also for our employees to use internally. We also write software for custom hardware. We also have the need for analytics. We have to deploy to PCs, mobile devices, tablets, and custom hardware. As you can see, you get very complex answers based on what you do.
5. How is your internal IT handled and how long has it been around? Is it a build-first kind or org or a buy first kind of org? My org, for example, uses Windows almost exclusively for desktop work. For running our software systems developed in-house, we use Linux almost exclusively except in those cases where we have IBM mainframes in place. For web developers, they all have Macs for web and mobile development. In a large org like ours, we use 5 or 6 flavors of assembly language, a couple of flavors of Cobol, Ruby, Python, bash scripts, perl scripts, C, C++, Java, Javascript, and a sprinkling of .net here and there. We mainly use Oracle but have DB2, Sql Server, Hadoop, MS Access, and probably 4 or 5 more flavors of other databases here and there. We use Teradata for long-term storage and reporting access. We have things like SAP and other major 3rd party software systems integrated with our ecosystem.
P.S. Although I tried to block it out and forget, we also have some very major financial systems still written in Visual Basic.