Answer:
much
Step-by-step explanation:
Salt is an uncountable noun and much ,more or many is used with uncountable nouns.
Sand is also uncountable noun.
An uncountable noun is one which cannot be counted easily like the grains of the sand, like the stars in the sky.
These are used with words much, more, many, less little or words which show a quantity .
Numbers cannot be used with such words. Like salt cannot be one two or three ,nor the stars or the sand.