If the Bombardment of A ${ } _ { 20 } ^ { 40 } \mathrm { Ca }$

If the bombardment of a ${ } _ { 20 } ^ { 40 } \mathrm { Ca }$
Nucleus with an alpha particle produces a deuteron,the other product is

A) ${ } _ { 21 } ^ { 42 } \mathrm { Sc }$
B) ${ } _ { 19 } ^ { 38 } \mathrm {~K}$
C) ${ } _ { 22 } ^ { 44 } \mathrm { Ti }$
D) none of these.