Assertion: Morarji Desai was unsuccessful in completing 5 years as the Prime Minister of India after winning the 1977 elections.
Reason: Due to unfavorable health conditions he had to resign from the post of Prime Minister of India in 1978.

The Assertion is correct but the Reason is incorrect.

The correct answer is Option 4 - The Assertion is correct but the Reason is incorrect.

Assertion: Morarji Desai was unsuccessful in completing 5 years as the Prime Minister of India after winning the 1977 elections. (CORRECT)
Reason: Due to unfavorable health conditions he had to resign from the post of Prime Minister of India in 1978. (INCORRECT)

Morarji Desai became the Prime Minister of India after the Janata Party coalition won the 1977 elections, ending the Congress party's long rule. However, his tenure was marked by internal conflicts within the coalition and challenges in managing the government which became the main cause of his resignation, not ill health.

The Janata Party government that came to power after the 1977 elections were far from cohesive. After the election, there was stiff competition among three leaders for the post of Prime Minister- Morarji Desai, who was the rival to Indira Gandhi ever since 1966-67; Charan Singh, leader of the Bharatiya Lok Dal and a farmers’ leader from UP; and Jagjivan Ram, who had vast experience as a senior minister in the Congress governments. Eventually, Morarji Desai became the Prime Minister but that did not bring the power struggle within the party to an end. The Janata Party split and the government which was led by Morarji Desai lost its majority in less than 18 months. Another government headed by Charan Singh was formed on the assurance of the support of the Congress party.