You are given data on three bonds.

Compare the bonds to rank them from the safest to the riskiest instrument.

\begin{tabular}{|l|c|c|c|} \hline Bond & Astra & Biba & Castro \\ \hline Rating (S\&P or Moody's long-term) & BBB & Baa2 & Ba1 \\ \hline Maturity (years) & 3.5 & 2.6 & 5.8 \\ \hline Coupon (annual) & 2.50 & 2.50 & 3.75 \\ \hline Yield to maturity (\%) & 3.3% & 2.7% & 11.0% \\ \hline Bid ask spread (over 100 par value) & 0.24 & 0.21 & 0.71 \\ \hline \end{tabular}