Answer:
a hypothesis
Step-by-step explanation:
Hypothesis: In statistics or research methods, the term "hypothesis" is described as an explanation or an idea that an investigator or a researcher can test through experimentation and study. A hypothesis is referred to as a guess or a theory outside science.
In other words, a hypothesis is determined as something which is considered as less than a well-established theory but more than a wild guess.
In the question above, Mr Grant has developed a hypothesis.