Galileo was convinced that natural phenomena, as manifestations of the laws of physics, would appear the same to someone on the deck of a ship moving smoothly and uniformly through the water as a person standing on land.
(A) water as a X
We need to maintain the parallelism here : “…to someone…to a person standing”
(B) water as to a CORRECT
(C) water; just as it would to X
It’s unclear what the ‘it’ is referring to. Is ‘it’ the natural phenomena? Ship?
(D) water, as it would to the X
This breaks the parallelism. The ‘it’ is also unclear. A subtle detail, but the use of the article ‘the’ to signify a person whose reference is understood is also wrong.
(E) water; just as to the X
‘just as’ is wrong.