Assertion:John Maynard Keynes is regarded as one of the most influential economics books of the nineteenth century.

Reasoning: John Maynard Keynes was also a shrewd foreign currency speculator.

Assertion (A) is not true but Reasoning (R) is correct.

The correct answer is Option 4: Assertion (A) is not true but Reasoning (R) is correct.

Assertion:John Maynard Keynes is regarded as one of the most influential economics books of the nineteenth century. This is incorrect. Keynes is regarded as one of the most influential economics books of the twentieth (not nineteenth  century).

Reasoning: John Maynard Keynes was also a shrewd foreign currency speculator. This is correct.

"John Maynard Keynes, British economist, was born in 1883. He was educated in King’s College, Cambridge, United Kingdom and later appointed its Dean. Apart from being a sharp intellectual he actively involved in international diplomacy during the years following the First World War. He prophesied the break down of the peace agreement of the War in the book The Economic Consequences of the Peace (1919). His book General Theory of Employment, Interest and Money (1936) is regarded as one of the most influential economics books of the twentieth century. He was also a shrewd foreign currency speculator."