**Core Concept**
The question is testing the ideal contraceptive method for a couple with infrequent sexual encounters, requiring a method that is convenient, easy to use, and effective in preventing pregnancy with minimal side effects.

**Why the Correct Answer is Right**
The barrier method, specifically condoms, is the ideal contraceptive for a couple living in different cities and meeting only occasionally. This is because barrier methods are easy to use, do not require any medical intervention or prescription, and are highly effective in preventing pregnancy when used correctly. Condoms also provide additional benefits, such as protection against sexually transmitted infections (STIs). The convenience and ease of use of barrier methods make them an attractive option for a couple with infrequent sexual encounters.

**Why Each Wrong Option is Incorrect**
**Option B:** IUCD (Intrauterine Contraceptive Device) requires a medical procedure for insertion and is not suitable for a couple with infrequent sexual encounters. IUCDs are more effective for couples with regular sexual activity and are not easily reversible.
**Option C:** Oral Contraceptive Pills (OCPs) require daily adherence and a prescription, making them less suitable for a couple with infrequent sexual encounters. OCPs also have potential side effects and interactions with other medications.
**Option D:** Depot Medroxyprogesterone Acetate (DMPA) is an injectable contraceptive that requires regular injections and has potential side effects, such as irregular bleeding and weight gain. It is not suitable for a couple with infrequent sexual encounters.

**Clinical Pearl / High-Yield Fact**
It's essential to note that barrier methods, such as condoms, are not only effective in preventing pregnancy but also provide protection against STIs. This is particularly important for couples with infrequent sexual encounters, as they may not have regular screening for STIs.

**✓ Correct Answer: A. Barrier method**