Final answer:
Old Tom' gin is a slightly sweet style of gin that became popular in the 18th century and is known for balancing strong botanical flavors. It is not an illegally-distilled spirit, nor is it made from malted barley, which would typically describe whiskey.
Step-by-step explanation:
Old Tom' gin is referred to as option 3, which states it is slightly sweet. This style of gin became popular in the 18th century in England and is indeed known for its sweetness compared to other types of gin. The sweetness in Old Tom gin can help balance the strong botanical flavors, making it a popular choice in certain classic cocktails. However, the incorrect options are: 1) which suggests that it is a euphemism for illegally-distilled spirit - this description is usually more suited to terms like 'bathtub gin' or 'moonshine', especially during the Prohibition era in the United States. Option 2) is also incorrect because Old Tom gin is not made from malted barley; that is more characteristic of whiskey, while gin is primarily distilled from grains like rye, wheat, or corn and flavored with botanicals including juniper. Option 4) 'none of the above' is not correct in this context.