Tay-sachs disease is due to the absence of an enzyme that
a. digests polysaccharides.
b. involves damage to liver cells.
c. prevents the breakdown of glycogen.
d. causes an accumulation of lipids in brain cells.

D. Causes an accumulation of lipids in brain cells

Explanation:

Tay-Sachs disease is caused by a genetic mutation in the HEXA gene. It is an autosomal recessive disease that causes the mutation on an enzyme, which metabolizes GM2 Ganglioside in nerve cells, this leads to a build-up of the molecule in brain cells. At the moment there is no cure for the disease, only support treatment is available.

your answer is "the 1950's"