Replace `than’ by `to’. `After’ Junior/Senior/ Prior. Use preposition `to’.

The given sentence is:

Ram is junior than (1) / Shyam and (2) / Ram is older (3) / than Ganesh. (4) / No Error (5)

The error in the sentence is in Part 1, where "junior" is used instead of "younger". The correct sentence would be:

Ram is younger than (1) / Shyam and (2) / Ram is older (3) / than Ganesh. (4) / No Error (5)

Here's a detailed explanation of the sentence and the error:

• The sentence compares the ages of three people - Ram, Shyam, and Ganesh.

• It uses the comparative degree of "junior" to compare Ram's age with Shyam's age, which is incorrect. The correct comparative degree to use here is "younger".

• The sentence correctly uses the comparative degree of "older" to compare Ram's age with Ganesh's age.

• The sentence is grammatically correct in all other aspects.

Here are some relevant definitions and formulas:

• Comparative degree: The comparative degree is used to compare two people or things. It is formed by adding -er to the end of the adjective (e.g. younger, older).

• Superlative degree: The superlative degree is used to compare three or more people or things. It is formed by adding -est to the end of the adjective (e.g. youngest, oldest).

In this sentence, the comparative degree is used to compare Ram's age with Shyam's age and Ganesh's age. However, the wrong comparative degree is used in Part 1 of the sentence. Hence, the answer is option A - 1.