**Core Concept**
The management of early pregnancy involves determining the viability of the pregnancy, which can be assessed through ultrasound evaluation. In cases of early pregnancy, the gestational sac and embryo should be visible on transvaginal ultrasound (TVS) by 5-6 weeks of gestation.

**Why the Correct Answer is Right**
The presence of a well-formed gestational sac with a crown-rump length (CRL) of 5mm at 5.6 weeks of gestation is consistent with an intrauterine pregnancy. The calculated gestational age is also in line with the expected ultrasound findings at this stage. However, the presence of slight vaginal spotting warrants further evaluation to rule out a potential miscarriage or ectopic pregnancy.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not address the need for further evaluation in the presence of vaginal spotting.
* **Option B:** This option is incorrect because it does not provide a clear plan for further management, and the use of progesterone alone may not be sufficient in cases of early pregnancy complications.
* **Option C:** This option is incorrect because it does not take into account the presence of a well-formed gestational sac and the calculated gestational age, which suggest an intrauterine pregnancy.

**Clinical Pearl / High-Yield Fact**
In cases of early pregnancy with vaginal bleeding, it is essential to perform a repeat ultrasound in 7-10 days to assess for embryo growth and viability. This can help differentiate between a viable intrauterine pregnancy and a potential miscarriage or ectopic pregnancy.

**Correct Answer: B. Repeat ultrasound in 7-10 days and continue to follow up.**