I am pretty positive that it's A. That was 95% a guess though.
The Answer is Mesomorphic.
Answer:The sliding filament model of muscle contraction, put forward by Hugh Huxley and Jean Hanson in 1954, is 60 years old in 2014. Formulation of the model and subsequent proof was driven by the pioneering work of Hugh Huxley (1924–2013).
Explanation:
