a
\(\lambda_{{p}}=\frac{{h}}{{P}_{{p}}} \quad \lambda_{{e}}=\frac{{h}}{{P}_{{e}}}\)

\(\because \lambda_{{p}}=\lambda_{{e}}\)

\(\Rightarrow {P}_{{p}}={P}_{{e}}\)

\(({K})_{{p}}=\frac{{P}_{{p}}^{2}}{2 {m}_{{p}}}\)

\(({K})_{{e}}=\frac{{P}_{{e}}^{2}}{2 {m}_{{e}}}\)

\({K}_{{D}}<{K}_{{e}} \text { as } {m}_{{p}}>{m}_{{e}}\)