Decide Between Stocks and Shares ISA and Cash ISA

You've an ISA allowance to use before the tax year ends and two options that sound similar. This works through the real difference, a protected fixed return versus a variable one, against your time horizon and how much risk you can stomach. It points to the right choice for your situation rather than a generic answer.

<context>
You have {ISA_ALLOWANCE} available to put into an ISA this tax year and are unsure whether a Stocks and Shares ISA or a Cash ISA is better for your situation. Your investment horizon is [number of years] and your attitude to risk is [low / medium / high].
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<task>
**Build a decision framework for ISA type selection:**
1. The fundamental difference: fixed return with capital protection vs variable return with growth potential
2. Inflation risk: what a cash ISA earning 4% actually returns when inflation is 3.5%
3. Time horizon rule of thumb: why the 5-year threshold is commonly cited and what the evidence says
4. Emergency fund status: why cash ISA makes sense for money you might need back quickly
5. Platform and product options: what to look for in a Stocks and Shares ISA provider

**Give a clear recommendation** based on the stated horizon and risk attitude, with conditions under which it would change.
</task>

<output_format>
- Decision tree: two key questions that determine the right path
- One-paragraph recommendation
- Red flags: two situations where the recommendation changes
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