\textbf{101.} Which of the following comparisons of the properties of steel and titanium is correct?
\textbf{A:} Melting point: Steel $>$ Titanium
\textbf{B:} Corrosion resistance: Titanium $>$ Steel
\textbf{C:} Resistance to reaction with particles present in seawater: Steel $<$ Titanium
\textbf{D:} Extent of use in aircraft construction: Steel $<$ Titanium
(1) ``A'' and ``B'' \hfill (2) ``A'' and ``B'' \hfill (3) ``B'' and ``D'' \hfill (4) ``C'' and ``D''