a. It's a phenomenon which results in the exertion of a force.
b.
Both.
c. The effect of mass interacting with space-time.
So....
1. Which 'gravity'... Einstienian or Newtonian ??
You forgot to answer the question.
a. Is gravity a Force?
It's a phenomenon which results in the exertion of a force.
That Rules Out Einsteinian 'gravity'...
"Einstein came up with the theory of general relativity (1915), the prototype of all modern gravitational theories. Its crucial ingredient, involving a colossal intellectual jump, is the concept of gravitation,
NOT AS A FORCE, but as a manifestation of the curvature of space-time..."
https://ned.ipac.caltech.edu/level5/ESSAYS/Bekenstein/bekenstein.html
That Creates another Problem, since your 'scientific community' doesn't follow Newtonian 'gravity'...
"...Einstein created his general theory of relativity—which provides *OUR MODERN UNDERSTANDING of gravity* —with the express purpose of expunging nonlocality from physics. Isaac Newton's gravity acted at a distance, as if by magic, and general relativity snapped the wand in two by showing that the curvature of spacetime, and *NOT AN INVISIBLE FORCE* , gives rise to gravitational attraction."
Musser George: How Einstein Revealed the Universe's Strange "Nonlocality"; Scientific American, November 2015.
https://www.scientificamerican.com/article/how-einstein-revealed-the-universe-s-strange-nonlocality/
Please Reconcile...?
b. Is 'gravity' a Scientific Law or Scientific Theory?
Both.
1. Elephant Hurling Fallacies are not answers.
2. Can't be both...
Newtonian Gravity is ...
"A Force".
EinSHtienian Gravity is
NOT ... "A Force".
They are 'Mutually Exclusive'. They're not even in the same Geometry for cryin out-loud:
Newtonian 'gravity' is Euclidean 3 Space; whereas, EinSHtienian 'gravity' is Pseudo- Riemannian 4 Space.
c. What is the CAUSE of 'gravity'...?
The effect of mass interacting with space-time.
Factually Incorrect...
Martin Rees; FRS, Astronomer Royal; Esteemed British cosmologist/ astrophysicist...
"
WHAT CAUSES GRAVITY AND MASS? Is the universe infinite? How did atoms assemble—on at least one planet around at least one star—into beings able to ponder these mysteries?
THESE QUESTIONS STILL BAFFLE ALL OF US. Rather than the “end of science” being nigh, we are still near the beginning of the cosmic quest."
http://assets.press.princeton.edu/chapters/p7115.pdf
regards