Step 1: Understanding the Concept: 
The question requires dating the painting to its correct period. This is based on the stylistic development of the Kangra school. 
 
Step 3: Detailed Explanation: 
The Kangra school of painting reached its zenith under the patronage of Raja Sansar Chand (ruled 1775-1823). The period from about 1785 to 1820 is considered the golden age of Kangra art, producing works of exceptional quality and refinement. This painting, with its mature and lyrical style, fits perfectly within this era. The period of 1810-20 represents the later part of this peak period, making it the most appropriate choice among the given options for this highly refined work. 
 
Step 4: Final Answer: 
Art historians suggest the time period of 1810-20 for its execution. 
Rearrange the following parts to form a meaningful and grammatically correct sentence: 
P. a healthy diet and regular exercise 
Q. are important habits 
R. that help maintain good physical and mental health 
S. especially in today's busy world