What is the daughter nucleus (nuclide produced when 103mo undergoes beta decay by emitting an electron?

Beta decay can happen in two ways as by emitting an electron or by emitting a positron. 
Here, an electron was emitted. In electron emitting beta decay, a neutron of element converts into a proton by emitting an electron. 

So the daughter element should have same number of mass number as parent element but there is difference between atomic numbers. Daughter element will have higher atomic number by 1 than parent element due to the conversion of a neutron.

Since parent atom is Mo (atomic number / proton number = 42), after a beta decay, the daughter nucleus should be the element Tc (atomic number = 43).

answer; /// i do believe that the correct answer is (c)nuclear bond