Step 1: Understanding the Concept
Protein-energy malnutrition has two main forms, marasmus and kwashiorkor.
Step 2: Marasmus
Marasmus results from a lack of both proteins and calories. It appears in infants below one year when breast feeding is replaced too early by food poor in both. The child becomes very thin with wasted muscles and wrinkled skin.
Step 3: Other disorders
Kwashiorkor occurs in older children getting enough calories but too little protein. Rickets is due to vitamin D deficiency and pellagra to niacin deficiency.
Step 4: Conclusion
These infants are likely to suffer from marasmus.
Final Answer:
The infants are likely to suffer from marasmus.
\[ \boxed{\text{(A) }\text{Marasmus}} \]