Explanation

Let's analyze each statement:

A. Not all risk is diversifiable. - TRUE

• This is correct because systematic risk (market risk) cannot be diversified away.

B. Unsystematic risk can be substantially reduced by diversification. - TRUE

• This is correct because unsystematic risk (firm-specific risk) can be reduced through diversification.

C. Systematic risk can be eliminated by holding securities in a well-diversified international stock portfolio. - FALSE

• This is incorrect because systematic risk affects all securities in the market and cannot be eliminated through diversification, even with international diversification.

D. None of above. - This would be incorrect since statement C is false.

Therefore, the least accurate statement is C.