Answer: Option (c) is the correct answer.
Explanation:
A positron is denoted as 
, a neutron is denoted as 
, an electron is denoted as 
, and a proton is denoted as 
.
Therefore, when 
will decay into 
this means there occurs decrease in its mass number. Hence, it means a neutron will be releasing during this reaction.
The reaction will be as follows.
The part of the experiment that’s is not touched by the independent variable and is for comparison is called the :
Control Group
