Step 1: Look at the Picture:
Work with dates. The artist lived from 1887 to 1972 and adopted the folk style from about the 1930s. The painting must come from that mature phase.
Step 2: Test option 1.
Option 1 (1950) is a late date and not the recorded date for this work, so drop it.
Step 3: Test option 2.
Option 2 (1955) is also later than the recorded date, so drop it.
Step 4: Test option 3.
Option 3 (1940) falls in the middle of his folk period, so it fits.
Step 5: Test option 4.
Option 4 (1840) is before his birth, so it is impossible.
Final Answer:
The date that fits the artist and the work is 1940, option 3.
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