वह विकल्प चुनें जो वाक्य के रेखांकित भाग को बेहतर बनाएगा। यदि कोई सुधार आवश्यक न हो, तो 'No Improvement' चुनें।

The scientists are busy to explore new ideas.

The correct answer is 'exploring'.

Key Points

• The error lies incorrect usage of infinitive after the adjective 'busy'.
• The word 'busy' is an adjective that means occupied with or concentrating on a particular activity or object of attention. In other words, it is describing the noun 'scientist', therefore, using infinitives with adjectives is incorrect.
• To describe the adjective we need an adjective complement. Adjective complement is a phrase that is used to describe the adjective or adds meaning to it.
  • Example: 
    • I considered leaving the Army.
    • He was busy doing his work.
• Thus, 'exploring' will be used in place of 'to explore'.
   

Correct sentence:  The scientists are busy exploring new ideas. 

Additional Information

•  Adjective: a word or phrase naming an attribute, added to or grammatically related to a noun to modify or describe it.