Fill in the blank with suitable preposition :

Although he promised to stand __________ me in difficulties he did not live up to it.

(A) To
(B) For
(C) Over
(D) Upon
(E) By

Choose the correct answer from the options given below:

(E) only

The correct answer is Option (1) - (E) only

The correct preposition in the blank is "By", as the phrase "stand by someone" means to support or remain loyal to someone during difficulties.

"Although he promised to stand by me in difficulties, he did not live up to it."

"Stand for" means to represent or tolerate.

• He stands for justice. (He represents/supports the idea of justice.)

Not appropriate here — it doesn’t mean to support someone in a personal sense.

"Stand over" means to supervise or monitor strictly.

• The teacher stood over the student while he did the test.
  Not relevant in the context of emotional or moral support.

"Stand to" means to be ready for action or to face consequences.

• Stand to attention.
  Again, not about standing with someone or supporting them.

"Stand upon" is a very formal or old-fashioned usage, meaning to insist on or demand.

• He stands upon ceremony.
  Doesn’t fit the context of personal support.